System and method for reducing interference from neighboring wireless devices

ABSTRACT

A technique is disclosed for reducing interference in a communication system including a plurality of wireless devices. A first device transmits a frame (e.g., an RTS frame or a CTS frame) to a second device, the frame including information from which a non-target third device may use to estimate potential interference at the first device based on a proposed transmission to a fourth device. The information includes at least one of an interference and sensitivity factor (ISF), transmit power, and reciprocity factor (a difference between an antenna receive gain and an antenna transmit gain). Using the information in the frame to estimate the potential interference at the first device, the third device may choose to proceed with the proposed transmission if the estimated potential interference is less than a threshold; or withdraw or modify the proposed transmission if the estimated potential interference is greater than or equal to a threshold.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application for patent is a Continuation of patentapplication Ser. No. 15/679,049 entitled SYSTEM AND METHOD FOR REDUCINGINTERFERENCE FROM NEIGHBORING WIRELESS DEVICES filed Aug. 16, 2017, andthis application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/382,170 entitled SYSTEM AND METHOD FORREDUCING INTERFERENCE FROM NEIGHBORING WIRELESS DEVICES filed Aug. 31,2016 and U.S. Provisional Application No. 62/382,707 entitled SYSTEM ANDMETHOD FOR REDUCING INTERFERENCE FROM NEIGHBORING WIRELESS DEVICES filedSep. 1, 2016. The disclosure of the prior applications are consideredpart of this application, and are hereby incorporated by reference.

FIELD

This disclosure relates generally to wireless communications, and inparticular, to a system and method for reducing interference fromneighboring wireless devices.

BACKGROUND

A communication system often includes three or more wireless devicesconfigured to communicate with each other at various times. Forinstance, a first wireless device may participate in a communicationsession with a second wireless device. During this communicationsession, a third wireless device may desire to communicate with a fourthwireless device. If the third wireless device is sufficiently close tothe first wireless device and/or the second wireless device, atransmission of a signal by the third wireless device intended for thefourth wireless device may produce interference at the first wirelessdevice and/or the second wireless device. The interference maysignificantly impact the communication session between the first andsecond wireless devices.

SUMMARY

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus comprises a processing systemconfigured to generate at least one frame including information fromwhich at least one first wireless node is able to estimate a potentialinterference at the apparatus; an interface configured to output the atleast one frame for transmission to at least one second wireless node.

Certain aspects of the present disclosure provide a method for wirelesscommunications. The method comprises generating at least one frameincluding information from which a first wireless node is able toestimate a potential interference at an apparatus configured to transmitthe at least one frame; and outputting the at least one frame fortransmission to at least one second wireless node.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus comprises means for generating atleast one frame including information from which at least one firstwireless node is able to estimate a potential interference at anapparatus; and means for outputting the at least one frame fortransmission to at least one second wireless node.

Certain aspects of the present disclosure provide a computer readablemedium having instructions stored thereon for generating at least oneframe including information from which at least one first wireless nodeis able to estimate a potential interference at an apparatus configuredto transmit the at least one frame; and outputting the at least oneframe for transmission to at least one second wireless node.

Certain aspects of the present disclosure provide a first wireless node.The first wireless node comprises a processing system configured togenerate at least one frame including information from which at leastone second wireless node is able to estimate a potential interference atthe first wireless node; and a transmitter configured to transmit the atleast one frame to at least one third wireless node.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus comprises an interface configuredto receive at least one first frame from a first wireless node; and aprocessing system coupled to the interface and configured to estimate apotential interference at the first wireless node based on informationin the at least one first frame and a proposed transmission scheme fortransmitting at least one second frame to a second wireless node; andperform an operation based on the estimated potential interference.

Certain aspects of the present disclosure provide a method for wirelesscommunications. The method comprises receiving at least one first framefrom a first wireless node; estimating a potential interference at thefirst wireless node based on the information in the at least one firstframe and a proposed transmission scheme for transmitting at least onesecond frame to a second wireless node; and performing an operationbased on the estimated potential interference.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus comprises means for receiving atleast one first frame from a first wireless node; means for estimating apotential interference at the first wireless node based on informationin the at least one first frame and a proposed transmission scheme fortransmitting at least one second frame to a second wireless node; andmeans for performing an operation based on the estimated potentialinterference.

Certain aspects of the present disclosure provide a computer readablemedium having instructions stored thereon for: receiving at least onefirst frame from a first wireless node; estimating a potentialinterference at the first wireless node based on information in the atleast one first frame and a proposed transmission scheme fortransmitting at least one second frame to a second wireless node; andperforming an operation based on the estimated potential interference.

Certain aspects of the present disclosure provide a wireless node. Thewireless node comprises a receiver configured to receive at least onefirst frame from a first wireless node; and a processing system coupledto the receiver configured to estimate a potential interference at thefirst wireless node based on information in the at least one first frameand a proposed transmission scheme for transmitting at least one secondframe to a second wireless node, and perform an operation based on theestimated potential interference.

Aspects of the present disclosure also provide various methods, means,and computer program products corresponding to the apparatuses andoperations described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an exemplary wirelesscommunication system in accordance with an aspect of the presentdisclosure.

FIG. 2 illustrates a block diagram of an exemplary access point and userterminal in accordance with another aspect of the present disclosure.

FIG. 3 illustrates a diagram of an exemplary modified Request to Send(RTS) frame in accordance with another aspect of the present disclosure.

FIG. 4 illustrates a diagram of an exemplary modified Clear to Send(CTS) frame in accordance with another aspect of the present disclosure.

FIG. 5 illustrates a diagram of an exemplary modified acknowledgement(ACK) frame in accordance with another aspect of the present disclosure.

FIG. 6 illustrates a block diagram of an exemplary communication systemin a first configuration in accordance with another aspect of thepresent disclosure.

FIG. 7 illustrates a block diagram of an exemplary communication systemin a second configuration in accordance with another aspect of thepresent disclosure.

FIG. 8 illustrates a block diagram of an exemplary communication systemin a third configuration in accordance with another aspect of thepresent disclosure.

FIG. 9 illustrates a flow diagram of an exemplary method of wirelesslycommunicating with another device in accordance with certain aspects ofthe disclosure.

FIG. 10 illustrates a flow diagram of another exemplary method ofwirelessly communicating with another device in accordance with certainaspects of the disclosure.

FIG. 11 illustrates a flow diagram of an exemplary method of reducing oreliminating interference at a wireless device in accordance with certainaspects of the disclosure.

FIG. 12 illustrates a block diagram of an exemplary device in accordancewith certain aspects of the present disclosure.

FIG. 13 illustrates a flow diagram of another exemplary method ofwirelessly communicating with another device in accordance with certainaspects of the disclosure.

FIG. 14 illustrates components capable of performing the operationsshown in FIG. 13, in accordance with certain aspects of the presentdisclosure.

FIG. 15 illustrates a flow diagram of another exemplary method ofwirelessly communicating with another device in accordance with certainaspects of the disclosure.

FIG. 16 illustrates components capable of performing the operationsshown in FIG. 15, in accordance with certain aspects of the presentdisclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Forexample, the transmission protocols may include institute of electricaland electronic engineers (IEEE) 802.11 protocol. In some aspects, the802.11 protocol may include the 802.11 ay and/or the 802.11ad protocols,as well as future protocols. The detailed description and drawings aremerely illustrative of the disclosure rather than limiting, the scope ofthe disclosure being defined by the appended claims and equivalentsthereof.

The techniques described herein may be used for various broadbandwireless communication systems, including communication systems that arebased on an orthogonal multiplexing scheme. Examples of suchcommunication systems include Spatial Division Multiple Access (SDMA),Time Division Multiple Access (TDMA), Orthogonal Frequency DivisionMultiple Access (OFDMA) systems, Single-Carrier Frequency DivisionMultiple Access (SC-FDMA) systems, and so forth. An SDMA system mayutilize sufficiently different directions to simultaneously transmitdata belonging to multiple access terminals. A TDMA system may allowmultiple access terminals to share the same frequency channel bydividing the transmission signal into different time slots, each timeslot being assigned to different access terminal. An OFDMA systemutilizes orthogonal frequency division multiplexing (OFDM), which is amodulation technique that partitions the overall system bandwidth intomultiple orthogonal sub-carriers. These sub-carriers may also be calledtones, bins, etc. With OFDM, each sub-carrier may be independentlymodulated with data. An SC-FDMA system may utilize interleaved FDMA(IFDMA) to transmit on sub-carriers that are distributed across thesystem bandwidth, localized FDMA (LFDMA) to transmit on a block ofadjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multipleblocks of adjacent sub-carriers. In general, modulation symbols are sentin the frequency domain with OFDM and in the time domain with SC-FDMA.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g.,nodes). In some aspects, a wireless node implemented in accordance withthe teachings herein may comprise an access point or an access terminal.

An access point (“AP”) may comprise, be implemented as, or known as aNode B, a Radio Network Controller (“RNC”), an evolved Node B (eNB), aBase Station Controller (“BSC”), a Base Transceiver Station (“BTS”), aBase Station (“BS”), a Transceiver Function (“TF”), a Radio Router, aRadio Transceiver, a Basic Service Set (“BSS”), an Extended Service Set(“ESS”), a Radio Base Station (“RBS”), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or known as asubscriber station, a subscriber unit, a mobile station, a remotestation, a remote terminal, a user terminal, a user agent, a userdevice, user equipment, a user station, or some other terminology. Insome implementations, an access terminal may comprise a cellulartelephone, a cordless telephone, a Session Initiation Protocol (“SIP”)phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, a Station (“STA”), or some other suitable processing deviceconnected to a wireless modem. Accordingly, one or more aspects taughtherein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, aportable computing device (e.g., a personal data assistant), anentertainment device (e.g., a music or video device, or a satelliteradio), a global positioning system device, or any other suitable devicethat is configured to communicate via a wireless or wired medium. Insome aspects, the node is a wireless node. Such wireless node mayprovide, for example, connectivity for or to a network (e.g., a widearea network such as the Internet or a cellular network) via a wired orwireless communication link.

FIG. 1 illustrates a block diagram of an exemplary wirelesscommunication system 100 with a plurality of wireless nodes, such asaccess points (APs) 110 and access terminals (ATs) 120. For simplicity,only one access point 110 is shown. An access point 110 is generally afixed station that communicates with access terminals 120 and may alsobe referred to as a base station or some other terminology. An accessterminal 120 may be fixed or mobile, and may be referred to as a mobilestation, a wireless device or some other terminology. The access point110 may communicate with one or more access terminals 120 a to 120 i atany given moment on the downlink and uplink. The downlink (i.e., forwardlink) is the communication link from the access point 110 to the accessterminals 120, and the uplink (i.e., reverse link) is the communicationlink from the access terminals 120 to the access point 110. An accessterminal 120 may also communicate peer-to-peer with another accessterminal 120. A system controller 130 couples to and providescoordination and control for the access points 110. The access point 110may communicate with other devices coupled to a backbone network 150.

In one example, the wireless communication system 100 utilizes directsequence spread spectrum (DSSS) modulation techniques in communicationbetween the access point 110 and access terminals 120. The use of spreadspectrum techniques allows for the system to readily manage and operatelonger inter symbol interference (ISI) channels. In particular, codedivision multiple access (CDMA), readily facilitates increases in usercapacity in systems of this size as compared to conventional cellularsystems. More specifically, the access point 110 may be within apredefined geographical region, or cell, using severalmodulator-demodulator units or spread-spectrum modems to processcommunication signals. During typical operations, a modem in the accesspoint 110 is assigned to each access terminal 120 as needed toaccommodate transfer of communication signals. If the modem employsmultiple receivers, then one modem accommodates diversity processing,otherwise multiple modems may be used in combination.

FIG. 2 illustrates a block diagram of the access point 110 (generally, afirst wireless node) and an access terminal 120, for example, one of theaccess terminals 120 a (generally, a second wireless node) in thewireless communication system 100. The access point 110 is atransmitting entity for the downlink and a receiving entity for theuplink. The access terminal 120 a is a transmitting entity for theuplink and a receiving entity for the downlink. As used herein, a“transmitting entity” is an independently operated apparatus or devicecapable of transmitting data via a wireless channel, and a “receivingentity” is an independently operated apparatus or device capable ofreceiving data via a wireless channel.

For transmitting data, the access point 110 comprises a transmit dataprocessor 220, a frame builder 222, a transmit processor 224, aplurality of transceivers 226 a through 226 n, a bus interface forconnecting the illustrated devices and components, and a plurality ofantennas 230 a through 230 n. The access point 110 also comprises acontroller 234 for controlling operations of the access point 110. Inone embodiment, antennas 230 a through 230 n form a multi antenna phasedarray for multiple, steerable beams that can be directed to specificusers. In this embodiment, isolation between users may be increasedusing the antenna array. The antennas may also be configured for equalgain beamforming (EGB) techniques and null steering techniques via phasecontrol.

In operation, the transmit data processor 220 receives data (e.g., databits) from a data source 215, and processes the data for transmission.For example, the transmit data processor 220 may encode the data (e.g.,data bits) into encoded data, and modulate the encoded data into datasymbols. The transmit data processor 220 may support differentmodulation and coding schemes (MCSs). For example, the transmit dataprocessor 220 may encode the data (e.g., using low-density parity check(LDPC) encoding) at any one of a plurality of different coding rates.Also, the transmit data processor 220 may modulate the encoded datausing any one of a plurality of different modulation schemes, including,but not limited to, binary phase-shift keying (BPSK), quadraturephase-shift keying (QPSK), quadrature amplitude modulation (QAM) (forexample, 16QAM, 64QAM, and 256QAM), and amplitude and phase-shift keyingor asymmetric phase-shift keying (APSK) (for example, 64APSK, 128APSK,and 256APSK).

In certain aspects, the controller 234 may send a command to thetransmit data processor 220 specifying which modulation and codingscheme (MCS) to use (e.g., based on channel conditions of the downlink),and the transmit data processor 220 may encode and modulate data fromthe data source 215 according to the specified MCS. It is to beappreciated that the transmit data processor 220 may perform additionalprocessing on the data such as data scrambling, and/or other processing.The transmit data processor 220 outputs the data symbols to the framebuilder 222.

The frame builder 222 constructs, or generates, a frame (also referredto as a packet), and inserts the data symbols into a data payload of theframe. The frame may include a preamble, a header, and the data payload.In one embodiment, the frame is any of a beacon frame, a probe requestframe, or a probe response frame. The frame may include interferenceinformation such as an interference sensitivity factor (ISF), transmitpower, or a reciprocity factor, in the form of a class as described ingreater detail below. The preamble may include a short training field(STF) sequence and a channel estimation field (CEF) sequence to assistthe access terminal 120 a in receiving the frame. The header may includeinformation related to the data in the payload such as the length of thedata and the MCS used to encode and modulate the data. This informationallows the access terminal 120 a to demodulate and decode the data. Thedata in the payload may be divided among a plurality of blocks, whereineach block may include a portion of the data and a guard interval (GI)to assist the receiver with phase tracking. The frame builder 222outputs the frame to the transmit processor 224.

The transmit processor 224 processes the frame for transmission on thedownlink. For example, the transmit processor 224 may support differenttransmission modes such as an orthogonal frequency-division multiplexing(OFDM) transmission mode and a single-carrier (SC) transmission mode. Inthis example, the controller 234 may send a command to the transmitprocessor 224 specifying which transmission mode to use, and thetransmit processor 224 may process the frame for transmission accordingto the specified transmission mode. The transmit processor 224 may applya spectrum mask to the frame so that the frequency constituent of thedownlink signal meets certain spectral requirements.

In certain aspects, the transmit processor 224 may supportmultiple-output-multiple-input (MIMO) transmission. In these aspects,the access point 110 may include multiple antennas 230 a through 230 nand multiple transceivers 226 a through 226 n (e.g., one for eachantenna). The transmit processor 224 may perform spatial processing onthe incoming frames and provide a plurality of transmit frame streamsfor the plurality of antennas. The transceivers 226 a through 226 nreceive and processes (e.g., converts to analog, amplifies, filters, andfrequency upconverts) the respective transmit frame streams to generatetransmit signals for transmission via the antennas 230 a through 230 n,respectively.

The transmit processor 224 may be configured to transmit a plurality oftraining signals associated with a transmit beamforming training portionof an 802.11 beamforming training protocol (e.g., 802.11ad, 802.11ay, orfuture beamforming training protocols) between the access point 110 andone or more access terminals 120 a. In one example, the beamformingtraining protocol may include sector level sweep (SLS) and a beamrefinement phase for transmission (BRP-Tx).

For transmitting data, the access terminal 120 a comprises a transmitdata processor 260, a frame builder 262, a transmit processor 264, aplurality of transceivers 266 a through 266 n, a bus interface forconnecting the illustrated devices and components, and a plurality ofantennas 270 a through 270 n (e.g., one antenna per transceiver). Theaccess terminal 120 a may transmit data to the access point 110 on theuplink, and/or transmit data to another access terminal 120 (e.g., forpeer-to-peer communication). The access terminal 120 a also comprises acontroller 274 for controlling operations of the access terminal 120 a.In one embodiment, antennas 270 a through 270 n form an antenna arrayfor multiple, steerable beams that can be directed to specific users. Inthis embodiment, isolation between users may be increased using theantenna array. The antennas may also be configured for equal gainbeamforming (EGB) techniques and null steering techniques via, forexample, phase control.

In operation, the transmit data processor 260 receives data (e.g., databits) from a data source 255, and processes (e.g., encodes andmodulates) the data for transmission. The transmit data processor 260may support different MCSs. For example, the transmit data processor 260may encode the data (e.g., using LDPC encoding) at any one of aplurality of different coding rates, and modulate the encoded data usingany one of a plurality of different modulation schemes, including, butnot limited to, BPSK, QPSK, 16QAM, 64QAM, 64APSK, 128APSK, 256QAM, and256APSK. In certain aspects, the controller 274 may send a command tothe transmit data processor 260 specifying which MCS to use (e.g., basedon channel conditions of the uplink), and the transmit data processor260 may encode and modulate data from the data source 255 according tothe specified MCS. It is to be appreciated that the transmit dataprocessor 260 may perform additional processing on the data. Thetransmit data processor 260 outputs the data symbols to the framebuilder 262.

The frame builder 262 constructs, or generates a frame, and inserts thereceived data symbols into a data payload of the frame. The frame mayinclude a preamble, a header, and the data payload. In one embodiment,the frame is a beacon frame. The beacon frame may include interferenceinformation such as an interference sensitivity factor (ISF), transmitpower, or a reciprocity factor, described in greater detail below. Thepreamble may include an STF sequence and a CEF sequence to assist theaccess point 110 and/or other access terminal 120 in receiving theframe. The header may include information related to the data in thepayload such as the length of the data and the MCS used to encode andmodulate the data. The data in the payload may be divided among aplurality of blocks where each block may include a portion of the dataand a guard interval (GI) assisting the access point 110 and/or otheraccess terminal 120 with phase tracking. The frame builder 262 outputsthe frame to the transmit processor 264.

The transmit processor 264 processes the frame for transmission. Forexample, the transmit processor 264 may support different transmissionmodes such as an OFDM transmission mode and an SC transmission mode. Inthis example, the controller 274 may send a command to the transmitprocessor 264 specifying which transmission mode to use, and thetransmit processor 264 may process the frame for transmission accordingto the specified transmission mode. The transmit processor 264 may applya spectrum mask to the frame so that the frequency constituent of theuplink signal meets certain spectral requirements.

The transceivers 266 a through 266 n receive and process (e.g., convertsto analog, amplifies, filters, and frequency upconverts) the output ofthe transmit processor 264 for transmission via the one or more antennas270 a through 270 n. For example, the transceiver 266 may up-convert theoutput of the transmit processor 264 to a transmit signal having afrequency in the 60 GHz range.

In certain aspects, the transmit processor 264 may supportmultiple-output-multiple-input (MIMO) transmission. In these aspects,the access terminal 120 may include multiple antennas 270 a through 270n and multiple transceivers 266 a through 266 n (e.g., one for eachantenna). The transmit processor 264 may perform spatial processing onthe incoming frame and provide a plurality of transmit frame streams forthe plurality of antennas 270 a through 270 n. The transceivers 266 athrough 266 n receive and process (e.g., converts to analog, amplifies,filters, and frequency upconverts) the respective transmit frame streamsto generate transmit signals for transmission via the antennas 270 athrough 270 n.

The transmit processor 264 may be configured to transmit a plurality oftraining signals associated with a transmit beamforming training portionof an 802.11 beamforming training protocol (e.g., 802.11ad, 802.11ay, orfuture beamforming training protocols) between the access point 110 andone or more access terminals 120 a. In one example, the beamformingtraining protocol may include sector level sweep (SLS) and a beamrefinement phase for transmission (BRP-Tx).

For receiving data, the access point 110 comprises a receive processor242, and a receive data processor 244. In operation, the transceivers226 a through 226 n receive a signal (e.g., from the access terminal 120a), and spatially process (e.g., frequency down-converts, amplifies,filters and converts to digital) the received signal. The receivedsignal(s) may also be processed such that the phase and gain can becontrolled with beamforming algorithms. The beamforming algorithms maycontrol the phase (i.e., phase shifting) and gain of each antenna, andinclude linear spatial techniques, such as a channel correlation matrixinversion (CCMI) technique, a minimum mean square error (MMSE)technique, an equal gain beamforming technique, and others. Thebeamforming algorithms may also include space-time techniques, such as aminimum mean square error linear equalizer (MMSE-LE) technique, adecision feedback equalizer (DFE) technique, a maximal ratio combiningtechnique (MRC), and others.

The receive processor 242 and the receive data processor 244 may beconfigured to receive a plurality of training signals associated with atransmit beamforming training portion of an 802.11 beamforming trainingprotocol (e.g., 802.11ad, 802.11ay, or future beamforming trainingprotocols) between the access point 110 and one or more access terminals120 a. For example, the beamforming training protocol may include sectorlevel sweep (SLS) and a beam refinement phase for receiving (BRP-Rx).

The receive processor 242 receives the outputs of the transceivers 226 athrough 226 n, and processes the outputs to recover data symbols. Forexample, the access point 110 may receive data (e.g., from the accessterminal 120 a) in a frame. In this example, the receive processor 242may detect the start of the frame using the STF sequence in the preambleof the frame. The receiver processor 242 may also use the STF forautomatic gain control (AGC) adjustment. The receive processor 242 mayalso perform channel estimation (e.g., using the CEF sequence in thepreamble of the frame) and perform channel equalization on the receivedsignal based on the channel estimation.

Further, the receiver processor 242 may estimate phase noise using theguard intervals (GIs) in the payload, and reduce the phase noise in thereceived signal based on the estimated phase noise. The phase noise maybe due to noise from a local oscillator in the access terminal 120 aand/or noise from a local oscillator in the access point 110 used forfrequency conversion. The phase noise may also include noise from thechannel. The receive processor 242 may also recover information (e.g.,MCS scheme) from the header of the frame, and send the information tothe controller 234. After performing channel equalization and/or phasenoise reduction, the receive processor 242 may recover data symbols fromthe frame, and output the recovered data symbols to the receive dataprocessor 244 for further processing.

The receive data processor 244 receives the data symbols from thereceive processor 242 and an indication of the corresponding multi-scalecontrol (MSC) scheme from the controller 234. The receive data processor244 demodulates and decodes the data symbols to recover the dataaccording to the indicated MSC scheme, and outputs the recovered data(e.g., data bits) to a data sink 246 for storage and/or furtherprocessing.

As discussed above, the access terminal 120 a may transmit data using anOFDM transmission mode or a SC transmission mode. In this case, thereceive processor 242 may process the receive signal according to theselected transmission mode. Also, as discussed above, the transmitprocessor 264 may support multiple-output-multiple-input (MIMO)transmission. In this case, the access point 110 includes multipleantennas 230 a through 230 n and multiple transceivers 226 a through 226n (e.g., one for each antenna). Each transceiver receives and processes(e.g., frequency downconverts, amplifies, filters, and converts todigital) the signal from the respective antenna. The receive processor242 may perform spatial processing on the outputs of the transceivers226 a through 226 n to recover the data symbols.

For receiving data, the access terminal 120 a comprises a receiveprocessor 282, and a receive data processor 284. In operation, thetransceivers 266 a through 266 n receive a signal (e.g., from the accesspoint 110 or another access terminal 120) via the respective antennas270 a through 270 n, and process (e.g., frequency downconverts,amplifies, filters and converts to digital) the received signal. Thereceived signal(s) may also be processed such that the phase and gaincan be controlled with beamforming algorithms. The beamformingalgorithms may control the phase (i.e., phase shifting) and gain of eachantenna, and include linear spatial techniques, such as a channelcorrelation matrix inversion (CCMI) technique, a minimum mean squareerror (MMSE) technique, an equal gain beamforming technique, and others.The beamforming algorithms may also include space-time techniques, suchas a minimum mean square error linear equalizer (MMSE-LE) technique, adecision feedback equalizer (DFE) technique, a maximal ratio combiningtechnique (MRC), and others.

The receive processor 282 and the receive data processor 284 may beconfigured to receive a plurality of training signals associated with atransmit beamforming training portion of an 802.11 beamforming trainingprotocol (e.g., 802.11ad, 802.11ay, or future beamforming trainingprotocols) between the access point 110 and one or more access terminals120 a. For example, the beamforming training protocol may include sectorlevel sweep (SLS) and a beam refinement phase for receiving (BRP-Rx).

The receive processor 282 receives the outputs of the transceivers 266 athrough 266 n, and processes the outputs to recover data symbols. Forexample, the access terminal 120 a may receive data (e.g., from theaccess point 110 or another access terminal 120) in a frame, asdiscussed above. In this example, the receive processor 282 may detectthe start of the frame using the STF sequence in the preamble of theframe. The receive processor 282 may also perform channel estimation(e.g., using the CEF sequence in the preamble of the frame) and performchannel equalization on the received signal based on the channelestimation.

Further, the receiver processor 282 may estimate phase noise using theguard intervals (GIs) in the payload, and reduce the phase noise in thereceived signal based on the estimated phase noise. The receiveprocessor 282 may also recover information (e.g., MCS scheme) from theheader of the frame, and send the information to the controller 274.After performing channel equalization and/or phase noise reduction, thereceive processor 282 may recover data symbols from the frame, andoutput the recovered data symbols to the receive data processor 284 forfurther processing.

The receive data processor 284 receives the data symbols from thereceive processor 282 and an indication of the corresponding MSC schemefrom the controller 274. The receiver data processor 284 demodulates anddecodes the data symbols to recover the data according to the indicatedMSC scheme, and outputs the recovered data (e.g., data bits) to a datasink 286 for storage and/or further processing.

As discussed above, the access point 110 or another access terminal 120may transmit data using an OFDM transmission mode or a SC transmissionmode. In this case, the receive processor 282 may process the receivesignal according to the selected transmission mode. Also, as discussedabove, the transmit processor 224 may supportmultiple-output-multiple-input (MIMO) transmission. In this case, theaccess terminal 120 a may include multiple antennas and multipletransceivers (e.g., one for each antenna). Each transceiver receives andprocesses (e.g., frequency downconverts, amplifies, filters, andconverts to digital) the signal from the respective antenna. The receiveprocessor 282 may perform spatial processing on the outputs of thetransceivers to recover the data symbols.

As shown in FIG. 2, the access point 110 also comprises a memorydevice(s) 236 coupled to the controller 234. The memory device(s) 236may store instructions that, when executed by the controller 234, causethe controller 234 to perform one or more of the operations describedherein. Similarly, the access terminal 120 a also comprises a memorydevice(s) 276 coupled to the controller 274. The memory device(s) 276may store instructions that, when executed by the controller 274, causethe controller 274 to perform the one or more of the operationsdescribed herein. The memory device(s) 236 and 276 may store data toassist the access point 110 and access terminal 120 a in estimatinginterference information at one or more neighboring devices, asdescribed in more detail further herein.

FIG. 3 illustrates a diagram of an exemplary modified Request to Send(RTS) frame, or “RTS-TRN” frame 300 in accordance with another aspect ofthe present disclosure. A wireless device (referred to herein as an“originating device”) may use an RTS frame to determine whether acommunication medium is available to send one or more data frames to a“destination device.” Typically, an RTS frame is sent when the size ofthe one or more data frames to be transmitted to the destination deviceexceeds a specified threshold. In response to receiving the RTS frame,the destination device sends a Clear to Send (CTS) frame back to theoriginating device if the communication medium available. In response toreceiving the CTS frame, the originating device sends the one or moredata frames to the destination device. In response to successfullyreceiving the one or more data frames, the destination device sends oneor more Acknowledgement (“ACK”) frames to the originating device. SuchRTS frame, CTS frame, and ACK frame are examples of media access control(MAC) frames.

The MAC may include a carrier sense multiple access/collision avoidance(CSMA/CA) based distributed coordination function (DCF) and a pointcoordination function (PCF). The DCF allows for access of a mediumwithout central control. The PCF is deployed at an access point 110 toprovide central control. The DCF and PCF utilize various gaps betweenconsecutive transmissions to avoid collisions. Transmissions may bereferred to as frames, and a gap between frames is referred to as aninter-frame spacing (IFS). Frames may be user data frames, controlframes or management frames.

With regard to the frame details, the RTS-TRN frame 300 comprises an RTSportion including a frame control field 310, a duration field 312, areceiver address field 314, a transmitter address field 316, a framecheck sequence field 318, and a control trailer field 320. As discussedin more detail herein, the control trailer 320 includes information thatallows a neighboring (non-destination) device to estimate potentialinterference at the originating device if the neighboring devicetransmits a signal pursuant to a communication session. Such informationmay include at least one of an interference sensitivity factor (ISF),transmit power P_(t), or a reciprocity factor G_(r)−G_(t) (a differencebetween the antenna receive gain and the antenna transmit gain).

For improved communication and interference reduction purposes asdiscussed in more detail in U.S. Provisional Patent application Ser. No.62/273,397 (which is incorporated herein by reference), the RTS-TRNframe 300 further includes a beam training sequence field 322 forconfiguring respective antennas of the destination device and one ormore neighboring devices. The destination device uses the beam trainingsequence field 322 to configure its antenna for directional receptionfrom and transmission to the originating device. The one or moreneighboring devices uses the beam training sequence field 322 toconfigure its antenna for transmission so as to reduce interference atthe originating device, such as by configuring its transmit antennaradiation pattern to have nulls aimed substantially at the direction ofthe originating device. The beam training sequence in the beam trainingsequence field 322 may be based on a Golay sequence.

The RTS portion of the RTS-TRN frame 300 may be configured as a standardRTS frame specified in the institute of electrical and electronicengineers (IEEE) 802.11 protocols. In this regard, the frame controlfield 310 includes the following subfields: a “protocol” subfield forspecifying a version associated with the RTS frame portion; a “type”subfield for indicating a type of the frame (e.g., type=01 for a controlframe); a “subtype” subfield for indicating a subtype of the frame(e.g., subtype=1011 indicates an RTS frame); and “ToDS” and “FromDS”subfields to indicate whether a distribution system sends and receivesthe control frames (e.g., ToDS=0 and FromDS=0 for an RTS frame).

Additionally, the frame control field 310 further includes the followingsubfields: a “More Fragments” subfield to indicate whether the frame isfragmented (e.g., More Fragments=0 for an RTS frame as it is notfragmented); a “Retry” subfield to indicate whether the frame should beretransmitted if not received (e.g., Retry=0 for an RTS frame as it isnot retransmitted); a “Power Management” subfield to indicate a powermanagement state of the sender after conclusion of the current frameexchange; a “More Data” subfield used in management and data frames(e.g., More Data=0 for an RTS frame); a “Protected Frame” subfield toindicate whether the frame is encrypted (e.g., Protected Frame=0 as anRTS frame is not encrypted); and an “Order” subfield to indicate anorder of associated frames (e.g., Order=0 for an RTS frame as the framecannot be transmitted out of order).

The duration field 312 of the RTS portion of the RTS-TRN frame 300provides an indication of an estimated duration for which theoriginating device will be communicating with the destination device.Or, in other words, the duration field 312 specifies an estimate of theduration in which the communication medium will be used to effectuatethe communication between the originating device and the destinationdevice. The duration may include the following cumulative durations: (1)duration of a Short Interframe Space (SIFS) between the end of thetransmission of the RTS frame and the beginning of the transmission ofthe CTS frame; (2) duration of the CTS frame; (3) duration of anotherSIFS between the end of the transmission of the CTS frame and thebeginning of the transmission of the one or more data frames; (4)duration of the one or more data frames; (5) duration of another SIFSbetween the end of the transmission of the one or more data frames andthe beginning of the transmission of the ACK frame; and (6) duration ofthe ACK frame. As discussed in more detail further herein, one or moreneighboring devices may use the duration to determine whether toestimate potential interference at the originating device based on aproposed transmission scheme.

The receiver address field 314 of the RTS portion of the RTS-TRN frame300 indicates the address (e.g., media access control (MAC) address) ofthe destination device. As discussed in more detail, devices thatreceive the RTS-TRN frame 300 may perform different operations dependingon whether the device is the destination device or a non-destinationneighboring device. The transmitter address field 316 of the RTS portionof the RTS-TRN frame 300 indicates the address (e.g., MAC address) ofthe originating device. The frame check sequence field 318 of the RTSportion of the RTS-TRN frame 300 includes a value that allows receivingdevices to determine the validity of at least some of the informationtransmitted via the RTS portion of the RTS-TRN frame 300.

As previously discussed, the control trailer 320 includes at least oneof an ISF, P_(t), or G_(r)−G_(t). A neighboring device that receives themodified RTS-TRN frame 300 may estimate potential interference at theoriginating device based on the received power level of the RTS-TRNframe 300, one or more of the information ISF, P_(t), or G_(r)−G_(t),its proposed transmit power, and its proposed antenna's own reciprocityfactor. The interference is the power level of a signal transmitted bythe neighboring device at the input of a receiver of the originatingdevice. If the estimated potential interference at the originatingdevice is too high (e.g., greater than or equal to a threshold), theneighboring device may perform any number of responsive operations, suchas withdraw the transmission of the proposed signal, choose a differenttransmit sector for transmitting the proposed signal, or reduce thetransmission power of the proposed signal if that is a suitable optionbased on whether the signal may be adequately received by a targetdevice.

Based on the ISF, a neighboring device may estimate potentialinterference at the originating device using the following equation:

P _(ra) =P _(rb) +P _(tb)+(G _(tb) −G _(rb))−ISF _(a)  Equation 1

Where P_(ra) is the potential interference or power level at thereceiver input of the originating device, P_(rb) is the power level ofthe RTS-TRN frame 300 at the receiver input of the neighboring device,P_(tb) is the proposed transmit power of the neighboring device,G_(tb)−G_(rb) is the proposed reciprocity factor of the neighboringdevice, and ISF_(a) is the interference sensitivity factor of theoriginating device.

Based on P_(t) and G_(r)−G_(t), a neighboring device may estimatepotential interference at the originating device using the followingequation:

P _(ra) =P _(rb) +P _(tb)+(G _(tb) −G _(rb))−P _(ta)(G _(ra) −G_(ta))  Equation 2

Where P_(ta) is the transmit power of the originating device, andG_(ra)−G_(ta) is the negative of the reciprocity factor of theoriginating device. That is, the interference sensitivity factor (ISF)is equal to the transmit power P_(t) plus the reciprocity factorG_(t)−G_(r).

Based on Pt (and not ISF or G_(r)−G_(t)), a neighboring device mayestimate potential interference at the originating device using thefollowing equation:

P _(ra) =P _(rb) +P _(tb)+(G _(tb) −G _(rb))−P _(ta)  Equation 3

As indicated, Equation 3 is an abbreviated version of Equation 2. Thatis, the reciprocity factor of the originating device is missing becauseit was not communicated to the neighboring device. In such case, theneighboring device may use Equation 3 to estimate the potentialinterference P_(ra) at the originating device with the assumption thatthe reciprocity factor of the originating device is zero (0).Alternatively, the neighboring device may make an assumption as to thereciprocity factor of the originating device and use Equation 2 withG_(ra)−G_(ta) being an assumed value.

Based on G_(r)−G_(t) (and not ISF or P_(t)), a neighboring device mayestimate potential interference at the originating device using thefollowing equation:

P _(ra) =P _(rb)+(G _(tb) −G _(rb))(G _(ra) −G _(ta))  Equation 4

As indicated, Equation 4 is an abbreviated version of Equation 2. Thatis, the difference between the proposed transmit power P_(tb) of theneighboring device and the transmit power P_(ta) of the originatingdevice is missing because P_(ta) was not communicated to the neighboringdevice. In such case, the neighboring device may use Equation 4 toestimate the potential interference P_(ra) at the originating devicewith the assumption that the proposed transmit power P_(tb) of theneighboring device is equal to the transmit power P_(ta) of theoriginating device. Alternatively, the neighboring device may make anassumption as to the difference in the transmit powers and use Equation2 with P_(tb)−P_(ta) being an assumed value. Alternatively, the ISF maybe related to the transmit power P_(ta) and the receive sensitivity ofthe originating device.

Any one of the parameters used to determine the ISF may be based on thetransmission and/or reception of a plurality of frames. For example, theoriginating device may transmit a plurality of frames with differenttransmit powers. Accordingly, the frames may include different transmitpower information in their respective control trailers. Accordingly, theISF may be determined based on an average of the transmit powers fortransmitting the frames, respectively. Alternatively, the ISF may bedetermined based on a maximum of the transmit powers for transmittingthe frames. Alternatively, the ISF may be determined based on all of thetransmit powers for transmitting the frames.

The neighboring device may use the information in the duration field 312to determine a time interval for which the originating device will becommunicating with the destination device. If, based on the durationfield 312, the originating device and the destination device will becommunicating during a proposed communication session between theneighboring device and a target device, the neighboring device mayestimate potential interference at the originating device for thepurpose of taking an appropriate action if necessary. If, on the otherhand, based on the duration field 312, the originating device and thedestination device will no longer be communicating during the proposedcommunication session, the neighboring device need not perform theinterference estimate.

As mentioned above, based on the estimate of the potential interferenceP_(ra) at the originating device, the neighboring device may performcertain operation. For example, if the potential interference P_(ra) isless than (or equal to) a threshold (such that the interference wouldnot be considered significant at the originating device, e.g., may notimpact the reception of communications from the destination device bythe originating device), the neighboring device may just continue to usethe proposed transmission scheme for communicating with a target device.The threshold may be defined as the maximum acceptable interferencewhere the phrase “less than (or equal to) a threshold” as used herein isapplicable. Alternatively, the threshold may be defined as the minimumunacceptable interference where the phrase “greater than or equal to” asused herein is applicable.

If the potential interference P_(ra) is greater than or equal to athreshold (such that the interference would be considered significant atthe originating device, e.g., may impact the reception of communicationsfrom the destination device by the originating device), the neighboringdevice may take actions to eliminate or reduce the potentialinterference at the originating device. For example, the neighboringdevice may withdraw from participating in a communication with thetarget device. Alternatively, the neighboring device may change thetransmission sector (to a lesser optimal sector) for communicating withthe target device; the use of the new sector would reduce the estimatedinterference to less than (or equal to) the threshold. Alternatively,the neighboring device may lower its proposed transmit power to reducethe estimated interference to less than (or equal to) the threshold, aslong as the lowered transmit power is acceptable for communicating withthe target device.

FIG. 4 illustrates a diagram of exemplary modified Clear to Send (CTS)frame, or CTS-TRN frame 400 in accordance with another aspect of thepresent disclosure. As previously discussed, a destination devicetransmits the CTS-TRN frame 400 to an originating device if thecommunication medium is available for transmission of one or more dataframes from the originating device to the destination device.

In particular, the modified CTS-TRN frame 400 comprises a CTS portionincluding a frame control field 410, a duration field 412, a receiveraddress field 414, a frame check sequence field 418, and a controltrailer 420. Similar to the control trailer 320 of the RTS-TRN frame300, the control trailer 420 of the CTS-TRN frame 400 includesinformation that allows a neighboring (non-destination) device toestimate potential interference at the destination device based on aproposed transmission scheme of the neighboring device. Again, suchinformation may include at least one of an interference sensitivityfactor (ISF), transmit power P_(t), or reciprocity factor G_(r)−G_(t)(the difference in the antenna receive gain and the antenna transmitgain).

For improved communication and interference reduction purposes asdiscussed in detail in U.S. Provisional Patent application Ser. No.62/273,397, the CTS-TRN frame 400 further includes a beam trainingsequence field 422 for configuring respective antennas of theoriginating device and one or more neighboring devices. The originatingdevice uses the beam training sequence field 422 to configure itsantenna for directional reception from and transmission to thedestination device. The one or more neighboring devices uses the beamtraining sequence field 422 to configure its antenna for transmission soas to reduce interference at the destination device, such as byconfiguring its transmit antenna radiation pattern to have a null aimedsubstantially at the direction of the destination device. The beamtraining sequence in the beam training sequence field 422 may be basedon a Golay sequence.

The frame control field 410 of the CTS portion of the CTS-TRN frame 400includes essentially the same subfields as that of the RTS portion ofthe RTS-TRN frame 300, as previously discussed. The subfields of theframe control field 410 include the same values as the subfields of theframe control field 310 of the RTS portion of RTS-TRN frame 300, whichthe exception that the subtype subfield of the frame control field 410is set to 1100 to indicate a CTS frame (instead of 1011 which indicatesan RTS frame).

The duration field 412 of the CTS portion of the CTS-TRN frame 400provides an indication of a remaining estimated duration for which theoriginating device will be communicating with the destination device.Or, in other words, the duration field 412 specifies an estimate of theremaining duration in which the communication medium will be used toeffectuate the communication between the originating device and thedestination device. In particular, the duration field 412 includes theduration indicated in the duration field 312 of the RTS portion ofRTS-TRN frame 300, except that it does not include the cumulativedurations of the CTS frame and the SIFS immediately before the CTSframe. More specifically, the duration may include the followingcumulative durations: (1) duration of a SIFS between the end of thetransmission of the CTS frame and the beginning of the transmission ofthe one or more data frames; (2) duration of the one or more dataframes; (3) duration of another SIFS between the end of the transmissionof the one or more data frames and the beginning of the transmission ofthe ACK frame; and (4) duration of the ACK frame.

The receiving address field 414 of the CTS portion of the CTS-TRN frame400 indicates the address (e.g., MAC address) of the originating device.The frame check sequence field 418 of the CTS portion of the CTS-TRNframe 400 includes a value that allows receiving devices to determinethe validity of at least some of the information transmitted via the CTSportion of the CTS-TRN frame 400.

As previously discussed, the control trailer 420 includes at least oneof an ISF, P_(t), or G_(r)−G_(t). A neighboring device that receives theCTS-TRN frame 400 may estimate potential interference at the destinationdevice based on the received power level of the CTS-TRN frame 400, oneor more of the information ISF, P_(t), or G_(r)−G_(t), its proposedtransmit power, and its proposed antenna's own reciprocity factor per,for example, using a suitable one of Equations 1-4. The neighboringdevice may perform the potential interference estimate if during aproposed subsequent transmission coincides with the communicationsession between the originating device and the destination device basedon the information in the duration field 412 of the CTS-TRN frame 400.

Similarly, if the estimated potential interference at the destinationdevice is too high (e.g., greater than or equal to a threshold), theneighboring device may perform any number of responsive actions toeliminate or reduce the potential interference at the destination deviceas previously discussed. For instance, the responsive action may includewithdrawing the transmission of a signal so as to eliminate thepotential interference at the destination device, choose a differenttransmission sector for transmitting a signal so as to reduce thepotential interference at the destination device, or reduce thetransmission power (again to reduce the potential interference at thedestination device) if the reduction in the transmit power is stillsuitable for communicating with a target device.

FIG. 5 illustrates a diagram of exemplary ACK frame 500 in accordancewith another aspect of the present disclosure. The ACK frame 500 may beconfigured as a standard ACK frame per IEEE 802.11 protocols. Aspreviously discussed, a destination device transmits the ACK frame 500to an originating device in response to successfully receiving the oneor more data frames from the originating device.

In particular, the ACK frame 500 includes a frame control field 510, aduration field 512, a receiver address field 514, and a frame checksequence field 518. The frame control field 510 of the ACK frame 500includes essentially the same subfields as that of the RTS-TRN frame 300and the CTS-TRN frame 400, respectively. The subfields of the framecontrol field 510 include the same values as the subfields of the framecontrol fields 310 and 410 of the RTS-TRN frame 300 and the CTS-TRNframe 400, respectively, which the exception that the subtype subfieldof the frame control field 510 is set to 1101 to indicate an ACK frame.

The duration field 512 of the ACK frame 500 provides an indication of aremaining estimated duration for which the originating device will becommunicating with the destination device. If, for example, the lastdata frame from the originating device indicates a 0 in the MoreFragments subfield of its frame control field, then there are no furtherdata transmissions from the originating device to the destinationdevice. Accordingly, in such case, the duration field 512 indicates a 0as there are no further communication between the originating device andthe destination device once the ACK frame is transmitted. If, on theother hand, the last data frame from the originating device indicates a1 in the More Fragments subfield of its frame control field, then thereare more subsequent data transmissions from the originating device tothe destination device. Accordingly, in such case, the duration field512 indicates an estimate of the remaining duration for which theoriginating device and the destination device will be communicatingafter the transmission of the ACK frame. As discussed below, suchestimated duration may be used by neighboring devices to determine if itneeds to perform an estimate of the potential interference at theoriginating device for a proposed future transmission.

The following description with reference to FIGS. 6-8 provides examplesof how the aforementioned MAC frames, in particular the RTS-TRN frame300 and the CTS-TRN frame 400, are used to improve communication betweenan originating device and a destination device, such as by at leasteliminating potential interference or reducing actual interference atthe originating device and destination device from transmission byneighboring devices.

FIG. 6 illustrates a block diagram of an exemplary communication system600 in a first configuration in accordance with another aspect of thepresent disclosure. As illustrated, the communication system 600includes a plurality of wireless devices, such as a first device 610, asecond device 620, a third device 630, and a fourth device 640. In thisexample, the first device 610 is an example of an originating devicethat will be transmitting one or more data frames to a destinationdevice, which, in this example, is the second device 620. Also, in thisexample, the third device 630 is an example of a neighboring device tothe first device 610 and the second device 620. Similarly, the fourthdevice 640 is another example of a neighboring device to the firstdevice 610 and the second device 620.

Each of the first device 610, the second device 620, the third device630, and the fourth device 640 includes an antenna with multiple antennaelements, allowing each of them to transmit and receive in anomnidirectional manner and in a directional manner. In the firstconfiguration, the first device 610 has configured its antenna fordirectional transmission (DIR-TX) aimed approximately at the seconddevice 620. The second device 620, the third device 630, and the fourthdevice 640 have configured their respective antennas for omnidirectionalreception (OMNI-RX).

In the first configuration, the first device 610, operating as anoriginating device, transmits the RTS-TRN frame 300 with the receiveraddress field 314 indicating the address of the second device 620. Inthis example, the second device 620, the third device 630, and thefourth device 640 are sufficiently close to the first device 610 toreceive the RTS-TRN frame 300. The second device 620 determines that itis the destination device based on the information in the receiveraddress field 314 in the RTS-TRN frame 300. Similarly, the third device630 and the fourth device 640 determine that they are not the intendeddevice (but merely neighboring devices to the first device 610) based onthe information in the receiver address field 314 in the RTS-TRN frame300.

As neighboring devices to the first device 610, the third device 630 andthe fourth device 640 both receive and store one or more of theinformation in the duration field 312 and the control trailer 320 of theRTS-TRN frame 300. As discussed, the information in the control trailer320 includes at least one of the interference sensitivity Factor (ISF),transmit power P_(t), or reciprocity factor (G_(r)−G_(t)) associatedwith the transmission of the RTS-TRN frame 300 by the first device 610.The third device 630 and the fourth device 640 also measure and storethe power levels of the RTS-TRN frame 300 at the inputs of theirrespective receivers. The stored information may be used in the futureto determine whether the third device 630 and/or the fourth device 640need to estimate the potential interference at the first device 610based on the information in the duration field 312 of the RTS-TRN frame300, and if so, estimate the potential interference at the first device610 based on the information (ISF, P_(t), and/or G_(r)−G_(t)) in thecontrol trailer 320 of the RTS-TRN frame 300 and a proposed transmissionscheme between the third device 630 and the fourth device 640.

FIG. 7 illustrates a block diagram of the exemplary communication system700 in a second configuration in accordance with another aspect of thepresent disclosure. In the second configuration, the second device 720has determined that it is the destination device and, in response,optionally uses the beam training sequence in the beam training sequencefield 322 of the received RTS-TRN 300 to configure its antenna fordirectional transmission aimed substantially at the first device 710.That is, the antenna of the second device 720 may be configured togenerate an antenna radiation pattern with a primary lobe (e.g., highestgain lobe) aimed substantially at the first device 710, and non-primarylobes (e.g., lobes having distinct gains lower than that of the primarylobe) aimed in other directions (e.g., not aimed at the first device710). In this example, the non-primary lobes are aimed approximately atthe third device 730 and fourth device 740, respectively.

In the second configuration, the second device 720 transmits the CTS-TRNframe 400 with its antenna optionally configured for directionaltransmission aimed substantially at the first device 710. In thisexample, the first device 710 receives the CTS-TRN frame 400. Also, inaccordance with this example, the third device 730 and fourth device 740both receive the CTS-TRN frame 400. The third device 730 and the fourthdevice 740 determine that they are not the intended device (but merelyneighboring devices to the second device 720) based on the informationin the receiver address field 414 in the CTS-TRN frame 400.

As neighboring devices to the second device 720, the third device 730and the fourth device 740 both receive and store one or more of theinformation in the duration field 412 and the control trailer 420 of theCTS-TRN frame 400. As discussed, the information in the control trailer420 includes at least one of the interference sensitivity Factor (ISF),transmit power P_(t), or reciprocity factor (G_(r)−G_(t)) associatedwith the transmission of the CTS-TRN frame 400 by the second device 720.The third device 730 and the fourth device 740 also measure and storethe power levels of the CTS-TRN frame 400 at the inputs of theirrespective receivers. The stored information may be used in the futureto determine whether the third device 730 and/or the fourth device 740need to estimate the potential interference at the second device 720based on the information in the duration field 412 of the CTS-TRN frame400, and if so, estimate the potential interference at the second device720 based on the information (ISF, P_(t), and/or G_(r)−G_(t)) in thecontrol trailer 420 of the CTS-TRN frame 400 and a proposed transmissionscheme between the third device 730 and the fourth device 740.

The interference information can be transmitted and received usingclasses via the CTS-TRN frame 400 and/or the RTS-TRN frame 300. In oneembodiment, a class may include one or more bits in a field of theframe. In another embodiment, the class may be defined by an arrangementof fields in the frame. The class may identify the actual interferenceat a device. Another device receiving the class may determine the actualinterference by using a lookup table stored on the other device, or bycomparing the received class with values stored in a memory, for examplein a central or cloud database.

FIG. 8 illustrates a block diagram of the exemplary communication system800 in a third configuration in accordance with another aspect of thepresent disclosure. In the third configuration, the first device 810determines that it is the intended receiving device of the CTS-TRN frame400 based on the address indicated in the receiver address field 414 ofthe CTS-TRN frame 400. In response to determining it is the intendedreceiving device of the CTS-TRN frame 400, the first device 810 mayoptionally use the beam training sequence in the beam training sequencefield 422 of the received CTS-TRN frame 400 to configure its antenna fordirectional transmission aimed substantially at the second device 820.That is, the antenna of the first device 810 is configured to generatean antenna radiation pattern with a primary lobe (e.g., highest gainlobe) aimed substantially at the second device 820 and non-primary lobesaimed in other directions.

Also, in the third configuration, the second device 820 may haveoptionally configure its antenna for directional reception (e.g.,primary antenna radiation lobe) aimed at the first device 810, as thesecond device 820 already knows the direction to the first device 810based on the beam training sequence in the beam training sequence field322 of the RTS-TRN frame 300 it has previously received. Thus, while theantenna of the first device 810 is configured for directionaltransmission to the second device 820, and the antenna of the seconddevice 820 is configured for directional reception from the first device810, the first device 810 transmits one or more data frames to thesecond device 820.

While the first device 810 is communicating with the second device 820,the third device 830 decides it needs to communicate with the fourthdevice 840 (e.g., transmit an RTS frame to the fourth device 840). Inresponse, the third device 830 determines a proposed transmission schemefor transmitting a signal (e.g., an RTS frame) to the fourth device 840.The proposed transmission scheme may include a proposed transmit powerP_(t) and a proposed antenna radiation pattern, which may becharacterized by a reciprocity factor G_(t)−G_(r). Then, the thirddevice 830 determines whether the first device 810 is currentlycommunicating with the second device 820 based on the information in oneor both of the duration fields 312 and 412 in the RTS-TRN frame 300 andCTS-TRN frame 400, respectively. If the third device 830 determines thatthe first device 810 is no longer communicating with the second device820 based on one or both of the duration fields 312 and 412, the thirddevice 830 proceeds with transmitting the signal (e.g., the RTS frame)to the fourth device 840 pursuant to the proposed transmission scheme.

If, on the other hand, the third device 830 determines that the firstdevice 810 is still communicating with the second device 820, the thirddevice 830 estimates the respective potential interferences at the firstdevice 810 and the second device 820 that would result if the thirddevice transmits a signal to the fourth device 840 pursuant to theproposed transmission scheme. The third device 830 may estimate thepotential interference at the first device 810 using a suitable one ofEquations 1-4, the information (e.g., ISF, P_(t), or G_(r)−G_(t)) in thecontrol trailer 320 of the RTS-TRN frame 300 received from the firstdevice 810, the power level of the RTS-TRN frame 300 at the input of thereceiver of the third device 830, and the transmit power and reciprocityfactor of the proposed transmission scheme. Similarly, the third device830 may estimate the potential interference at the second device 820using a suitable one of Equations 1-4, the information (e.g., ISF,P_(t), or G_(r)−G_(t)) in the control trailer 420 of the CTS-TRN frame400 received from the second device 820, the power level of the CTS-TRNframe 400 at the input of the receiver of the third device 830, and thetransmit power and reciprocity factor of the proposed transmissionscheme.

If the third device 830 determines that the respective potentialinterference estimates at both the first device 810 and the seconddevice 820 are less than (or equal to) a threshold (where the respectiveinterferences would not significantly impact the communications betweenthe first device 810 and the second device 820), the third device 830proceeds with transmitting the signal (e.g., the RTS frame) to thefourth device 840 pursuant to the proposed transmission scheme.

If, on the other hand, the third device 830 determines that theestimated potential interference at either or both the first device 810and the second device 820 is greater than or equal to the threshold(where the respective interferences would significantly impact thecommunications between the first device 810 and the second device 820),the third device 830 may perform a particular action to eliminate orreduce interferences at the first device 810 and the second device 820.

For example, the third device 830 may decide to withdraw thetransmission of the signal (e.g., the RTS frame) to the fourth device840. The third device 830 may withdraw the transmission until the firstdevice 810 and the second device 820 cease communicating with each otherbased on one or more of the duration fields 312 and 412 in the RTS-TRNframes 300 and CTS-TRN frames 400, respectively. Thus, after the firstdevice 810 and second device 820 cease communicating, the third device830 may transmit the signal (e.g., an RTS frame) to the fourth device840 pursuant to the proposed transmission scheme.

Alternatively, the third device 830 may decide to change thetransmission sector pursuant to the proposed transmission scheme toreduce the interferences at one or both the first device 810 and thesecond device 820. For example, the third device 830 may have selectedsector “0” for transmission of a signal (e.g., an RTS frame) to thefourth device 840 pursuant to the proposed transmission scheme. However,due to the estimated potential interference at the second device 820being greater than or equal to the threshold, the third device 830 maydecide to select sector “7” for transmission of the signal. In suchcase, the transmission of the signal via sector “7” results in anestimated potential interference at both the first device 810 and thesecond device 820 being less than (or equal to) the threshold. In thisexample, the original estimated interference at the first device 810 mayhave already been less than (or equal to) the threshold; and thus, thechanging of the transmission sector from “0” to “7” is due to theestimated interference at the second device 820, not the first device810. Accordingly, the third device 830 may proceed with transmitting thesignal (e.g., an RTS frame) to the fourth device 840 via sector “7”pursuant to the modified transmission scheme.

As another example of modifying the proposed transmission scheme, thethird device 830 may reduce the transmit power of the proposedtransmission scheme to reduce the interference at one or both the firstdevice 810 and the second device 820. For example, the transmit power ofthe proposed transmission scheme may result in the estimated potentialinterference at the second device 820 being greater than or equal to thethreshold. However, as a result of the reduced transmit power, theestimated potential interference at the second device 820 is less than(or equal to) the threshold. Similarly, in this example, the estimatedpotential interference at the first device 810 may have already beenless than (or equal to) the threshold; and thus, the reduction in thetransmit power is due to the estimated potential interference at thesecond device 820, not the first device 810. The third device 830 maynow proceed with transmitting the signal (e.g., an RTS frame) to thefourth device 840 with the transmit power of the modified transmissionscheme.

In response to receiving the signal (e.g., an RTS frame) from the thirddevice 830, the fourth device 840 determines a proposed transmissionscheme for sending a responsive signal (e.g., a CTS frame) to the thirddevice 830. Similarly, the proposed transmission scheme may include aproposed transmit power P_(t) and a proposed antenna radiation pattern,which may be characterized by a reciprocity factor G_(t)-G_(r). Then,the fourth device 840 determines whether the first device 810 iscurrently communicating with the second device 820 based on theinformation in one or both of the duration fields 312 and 412 in theRTS-TRN frame 300 and the CTS-TRN frame 400, respectively. If the fourthdevice 840 determines that the first device 810 is no longercommunicating with the second device 820 based on one or both of theduration fields 312 and 412, the fourth device 840 proceeds withtransmitting the signal (e.g., the CTS frame) to the third device 830pursuant to the proposed transmission scheme.

If, on the other hand, the fourth device 840 determines that the firstdevice 810 is still communicating with the second device 820, the fourthdevice 840 estimates the respective potential interferences at the firstdevice 810 and the second device 820 that would result if the fourthdevice 840 transmits the signal to the third device 830 pursuant to theproposed transmission scheme. The fourth device 840 may estimate thepotential interference at the first device 810 using a suitable one ofEquations 1-4, the information (e.g., ISF, P_(t), or G_(r)−G_(t)) in thecontrol trailer 320 of the RTS-TRN frame 300 received from the firstdevice 810, the power level of the RTS-TRN frame 300 at the input of thereceiver of the fourth device 840, and the transmit power andreciprocity factor of the proposed transmission scheme. Similarly, thefourth device 840 may estimate the potential interference at the seconddevice 820 using a suitable one of Equations 1-4, the information (e.g.,ISF, P_(t), or G_(r)−G_(t)) in the control trailer 420 of the CTS-TRNframe 400 received from the second device 820, the power level of theCTS-TRN frame 400 at the input of the receiver of the fourth device 840,and the transmit power and reciprocity factor of the proposedtransmission scheme.

If the fourth device 840 determines that the respective potentialinterference estimates at both the first device 810 and the seconddevice 820 are less than (or equal to) a threshold (where the respectiveinterferences would not significantly impact the communications betweenthe first device 810 and the second device 820), the fourth device 840proceeds with transmitting the signal (e.g., the CTS frame) to the thirddevice 830 pursuant to the proposed transmission scheme.

If, on the other hand, the fourth device 840 determines that theestimated potential interference at either or both the first device 810and the second device 820 is greater than or equal to the threshold(where the respective interference(s) would significantly impact thecommunications between the first device 810 and the second device 820),the fourth device 840 may perform a particular action to eliminate orreduce the interferences at the first device 810 and the second device820.

For example, the fourth device 840 may decide to withdraw thetransmission of the signal (e.g., the CTS frame) to the third device830. The fourth device 840 may withdraw the transmission until the firstdevice 810 and the second device 820 cease communicating with each otherbased on one or more of the duration fields 312 and 412 in the RTS-TRNframe 300 and the CTS-TRN frame 400, respectively. Thus, after the firstdevice 810 and second device 820 cease communicating, the fourth device840 may transmit the signal (e.g., the CTS frame) to the third device830 pursuant to the proposed transmission scheme.

Alternatively, the fourth device 840 may decide to change thetransmission sector pursuant to the proposed transmission scheme toreduce the interferences at one or both the first device 810 and thesecond device 820. For example, the fourth device 840 may have selectedsector “3” for transmission of a signal (e.g., a CTS frame) to the thirddevice 830 pursuant to the proposed transmission scheme. However, due tothe estimated potential interference at the first device 810 beinggreater than or equal to the threshold, the fourth device 840 may decideto select sector “4” for transmission of the signal. In such case, thetransmission of the signal via sector “4” results in an estimatedinterferences at both the first device 810 and the second device 820being less than (or equal to) the threshold. In this example, theoriginal estimated interference at the second device 820 may havealready been less than (or equal to) the threshold; and thus, thechanging of the transmission sector from “3” to “4” is due to theestimated interference at the first device 810, not the second device820. Accordingly, the fourth device 840 may proceed with transmittingthe signal (e.g., a CTS frame) to the third device 830 via sector “4”pursuant to the modified transmission scheme.

As another example of modifying the proposed transmission scheme, thefourth device 840 may reduce the transmit power of the proposedtransmission scheme to reduce the interference at one or both the firstdevice 810 and the second device 820. For example, the transmit power ofthe proposed transmission scheme may result in the estimated potentialinterference at the first device 810 being greater than or equal to thethreshold. However, as a result of the reduced transmit power, theestimated interference at the first device 810 is less than (or equalto) the threshold. Similarly, in this example, the original estimatedinterference at the second device 820 may already have been less than(or equal to) the threshold; and thus, the reduction in the transmitpower is due to the estimated interference at the first device 810, notthe second device 820. The fourth device 840 may now proceed withtransmitting the signal (e.g., a CTS frame) to the third device 830 viawith the transmit power of the modified transmission scheme. It shouldbe noted that device 610 may correspond to devices 710 and 810.Similarly, devices 620, 630, and 640 may correspond to devices 720 and820, 730 and 830, and 740 and 840, respectively.

FIG. 9 illustrates a flow diagram of an exemplary method 900 ofwirelessly communicating with another device in accordance with certainaspects of the disclosure. The method 900 may be implemented by anoriginating device, such as the first device (610, 710, 810), whichtransmits an RTS-TRN frame 300 for communication with a destinationdevice, for example, the second device (620, 720, 820).

The method 900 includes the originating device configuring its antennafor transmitting in a directional manner aimed approximately at adestination device (block 902). For example, the originating device mayhave previously communicated with or intercepted a transmission from thedestination device allowing the originating device to estimate adirection towards the destination device. In this regard, with referenceto the access point 110 or access terminal 120 illustrated in FIG. 2,the transmit processor 224 or 264 may configure the transceivers 226 athrough 226 n or 266 a through 266 n to generate signals for theantennas 230 a through 230 n or 270 a through 270 n so that an antennaradiation pattern is generated with a primary lobe aimed approximatelyat the destination device, respectively. As it is well known, thetransceivers 226 a through 226 n or transceivers 266 a through 266 n mixthe respective signals generated by the transmit processor 224 or 264with different local oscillator signals having distinct relativeamplitude/phases (e.g., also referred to as weights) to produceconstructive interference to generate a primary lobe, constructive anddestructive interference to generate non-primary lobes, and destructiveinterference to generate nulls.

The method 900 further comprises generating and transmitting an RTS-TRN300 (including at least one of the ISF, P_(t), or G_(r)−G_(t) in thecontrol trailer 320) to the destination device via the antenna while theantenna is configured for directional transmission aimed approximatelyat the destination device (block 904). The information (e.g., at leastone of the ISF, P_(t), or G_(r)−G_(t)) in the control trailer 320 is anexample of information that may be used by a neighboring(non-destination) device for estimating potential interference at theoriginating device. In this regard, with reference to the access point110 or access terminal 120 illustrated in FIG. 2, the transmit dataprocessor 220 or 260 generates the data symbols for the RTS-TRN frame300 based on data received from a data source 215 or 255. The framebuilder 222 or 262 generates the RTS-TRN frame 300 including the datasymbols associated with the RTS portion of the RTS-TRN frame 300 and thebeam training sequence in the beam training sequence field 322. Thetransmit processor 224 or 264 acts as an interface for outputting theRTS-TRN frame 300 for transmission to the destination device.

The method 900 further comprises receiving the CTS-TRN frame 400(including at least one of the ISF, P_(t), or G_(r)−G_(t) in the controltrailer 420) from the destination device via the antenna while theantenna is configured to receive in an omnidirectional manner (block906). The information (e.g., at least one of the ISF, P_(t), orG_(r)−G_(r)) in the control trailer 420 is an example of informationthat may be used by a neighboring (non-destination) device forestimating potential interference at the destination device. In thisregard, with reference to the access point 110 or access terminal 120illustrated in FIG. 2, the receive processor 242 or 282 may configurethe transceivers 226 a through 226 n or 266 a through 266 n to configurethe antennas 230 a through 230 n or 270 a through 270 n to receivesignals in an omnidirectional manner, respectively.

The method 900 further comprises optionally configuring the antenna fordirectional transmission to the destination device based on the beamtraining sequence in the beam training sequence field 422 of the CTS-TRNframe 400 received from the destination device (block 908). Similarly,with reference to the access point 110 or access terminal 120illustrated in FIG. 2, the transmit processor 224 or 264 may configurethe transceivers 226 a through 226 n or 266 a through 266 n to generatesignals for the antennas 230 a through 230 n or 270 a through 270 n sothat an antenna radiation pattern is generated with a primary lobe aimedsubstantially at the destination device, respectively.

The method 900 further comprises generating and transmitting one or moredata or control frames to the destination device via the antenna whilethe antenna is configured for directional transmission aimed at thedestination device (block 910). Similarly, with reference to the accesspoint 110 or access terminal 120 illustrated in FIG. 2, the transmitdata processor 220 or 260 generates the data symbols for the one or moredata or control frames based on data received from a data source 215 or255. The frame builder 222 or 262 generates the one or more data orcontrol frames. The transmit processor 224 or 264 acts as an interfacefor outputting the one or more data or control frames for transmissionto the destination device.

The method 900 further comprises receiving one or more ACK, data, or ACKand data frames from the destination device via the antenna while theantenna is configured to receive in an omnidirectional manner oroptionally in a directional manner aimed at the destination device(block 912). In this regard, with reference to the access point 110 oraccess terminal 120 illustrated in FIG. 2, the receive processor 242 or282 may configure the transceivers 226 a through 226 n or 266 a through266 n to configure the antennas 230 a through 230 n or 270 a through 270n to receive signals in an omnidirectional manner, respectively.Alternatively, the receive processor 242 or 282 may configure thetransceivers 226 a through 226 n or 266 a through 266 n to configure theantennas 230 a through 230 n or 270 a through 270 n to receive signalsin a directional manner aimed at the destination device, respectively.

The method 900 further comprises reconfiguring the antenna to receive anin omnidirectional manner once the communications with the destinationdevice has ceased (block 914). In this regard, with reference to theaccess point 110 or access terminal 120 illustrated in FIG. 2, thereceive processor 242 or 282 may configure the transceivers 226 athrough 226 n or 266 a through 266 n to configure the antennas 230 athrough 230 n or 270 a through 270 n to receive signals in anomnidirectional manner, respectively.

FIG. 10 illustrates a flow diagram of another exemplary method 1000 ofwirelessly communicating with another device in accordance with certainaspects of the disclosure. The method 1000 may be implemented by adestination device, such as the second device (620, 720, 820), whichtransmits the CTS-TRN frame 400 in response to receiving an RTS-TRNframe 300 from an originating device, such as the first device (610,710, 810).

The method 1000 comprises configuring its antenna for receiving signalsin an omnidirectional manner (block 1002). In this regard, withreference to the access point 110 or access terminal 120 illustrated inFIG. 2, the receive processor 242 or 282 may configure the transceivers226 a through 226 n or 266 a through 266 n to configure the antennas 230a through 230 n or 270 a through 270 n to receive signals in anomnidirectional manner, respectively.

The method 1000 further comprises receiving an RTS-TRN frame 300(including at least one of the ISF, P_(t), or G_(r)−G_(t) in the controltrailer 320) from the originating device while the antenna is configuredto receive in an omnidirectional manner (block 1004). The information(e.g., at least one of the ISF, P_(t), or G_(r)−G_(r)) in the controltrailer 320 is an example of information that may be used by aneighboring (non-destination) device for estimating potentialinterference at the originating device. In this regard, with referenceto the access point 110 or access terminal 120 illustrated in FIG. 2,the receive processor 242 or 282, controller 234 or 274, and receivedata processor 244 or 284 operate together to process the receivedRTS-TRN frame 300 to extract the data from the RTS-TRN frame 300,respectively. The data informs the destination device of the identity ofthe originating device (e.g., based on the data in the transmitteraddress field 316 of the RTS-TRN frame 300), that the originating devicedesires to communicate with the destination device (e.g., based on thedata in the frame control field 310 that indicates that the frame is anRTS type frame), and that the destination device is the intendedreceiver for the RTS-TRN frame 300 (e.g., based on the data in thereceiver address field 314 of the RTS-TRN frame 300).

The method 1000 further comprises optionally configuring its antenna fortransmitting in a directional manner aimed substantially at theoriginating device based on the beam training sequence in the beamtraining sequence field 322 of the received RTS-TRN frame 300 (block1006). In this regard, with reference to the access point 110 or accessterminal 120 illustrated in FIG. 2, the transmit processor 224 or 264may configure the transceivers 226 a through 226 n or 266 a through 266n to generate signals for the antennas 230 a through 230 n or 270 athrough 270 n so that an antenna radiation pattern is generated with aprimary lobe aimed substantially at the originating device,respectively.

The method 1000 further comprises generating and transmitting theCTS-TRN frame 400 (including at least one of the ISF, P_(t), orG_(r)−G_(t) in the control trailer 420) to the originating device viathe antenna while the antenna is configured for directional transmissionaimed at the originating device (block 1008). The information (e.g., atleast one of the ISF, P_(t), or G_(r)−G_(t)) in the control trailer 420is an example of information that may be used by a neighboring(non-destination) device for estimating potential interference at thedestination device. In this regard, with reference to the access point110 or access terminal 120 illustrated in FIG. 2, the transmit dataprocessor 220 or 260 generates the data symbols for the CTS-TRN frame400 based on data received from a data source 215 or 255. The framebuilder 222 or 262 generates the CTS-TRN frame 400 including the datasymbols associated with the CTS portion of the CTS-TRN frame 400 and thebeam training sequence in the beam training sequence field 422. Thetransmit processor 224 or 264 acts as an interface for outputting theCTS-TRN frame 400 for transmission to the originating device.

The method 1000 further comprises receiving one or more data or controlframes from the destination device via the antenna while the antenna isconfigured to receive in an omnidirectional manner or optionally in adirectional manner aimed substantially at the originating device basedon the beam training sequence previously received via the RTS-TRN frame300 (block 1010). In this regard, with reference to the access point 110or access terminal 120 illustrated in FIG. 2, the receive processor 242or 282 may configure the transceivers 226 a through 226 n or 266 athrough 266 n to configure the antennas 230 a through 230 n or 270 athrough 270 n to receive signals in an omnidirectional manner,respectively. Alternatively, the receive processor 242 or 282 mayconfigure the transceivers 226 a through 226 n or 266 a through 266 n toconfigure the antennas 230 a through 230 n or 270 n through 270 n toreceive signals in a directional manner aimed at the originating device,respectively. Further, in this regard, with reference to the accesspoint 110 or access terminal 120 illustrated in FIG. 2, the receiveprocessor 242 or 282, controller 234 or 274, and receive data processor244 or 284 operate together to process the received one or more data orcontrol frames to extract information therefrom, respectively.

The method 1000 further comprises generating and transmitting one ormore ACK, data, or ACK and data frames to the originating device via theantenna while the antenna is configured for directional transmissionaimed at the originating device (block 1012). Similarly, with referenceto the access point 110 or access terminal 120 illustrated in FIG. 2,the transmit data processor 220 or 260 generates the data symbols forthe one or more data or control frames based on data received from adata source 215 or 255. The frame builder 222 or 262 generates the oneor more data or control frames. The transmit processor 224 or 264 actsas an interface for outputting the one or more data or control framesfor transmission to the originating device.

The method 1000 further comprises reconfiguring the antenna to receivean in omnidirectional manner once the communications with theoriginating device is completed (block 1014). In this regard, withreference to the access point 110 or access terminal 120 illustrated inFIG. 2, the receive processor 242 or 282 may configure the transceivers226 a through 226 n or 266 a through 266 n to configure the antennas 230a through 230 n or 270 a through 270 n to receive signals in anomnidirectional manner, respectively.

FIG. 11 illustrates a flow diagram of an exemplary method 1100 ofreducing or eliminating interference at a wireless device in accordancewith certain aspects of the disclosure. The method 1100 may beimplemented by a neighboring device to an originating device or adestination device. For example, the method 1100 may be implemented atthe third device (630, 730, 830) to reduce or eliminate interference atthe first device (610, 710, 810) or the second device (620, 720, 820)due to a proposed transmission scheme selected by the third device (630,730, 830). Similarly, the method 1100 may be implemented at the fourthdevice (640, 740, 840) to reduce or eliminate interference at the firstdevice (610, 710, 810) or the second device (620, 720, 820) due to aproposed transmission scheme selected by the fourth device (640, 740,840).

The method 1100 includes receiving an RTS-TRN frame 300 or a CTS-TRNframe 400 from a neighboring device (block 1102). The RTS-TRN frame 300or CTS frame 400 may have been received via an antenna configured toreceive in an omnidirectional manner. In this regard, with reference tothe access point 110 or access terminal 120 illustrated in FIG. 2, thereceive processor 242 or 282 may have configured the transceivers 226 athrough 226 n or 266 a through 266 n to configure the antennas 230 athrough 230 n or 270 a through 270 n to receive signals in anomnidirectional manner, respectively.

The method 1100 further includes generating an indication of the powerlevel of the RTS-TRN frame 300 or CTS-TRN frame 400 at the input of thereceiver and processing the frame to extract the duration information inthe duration field 312 or 412, and at least one of the ISF, P_(t), orG_(r)−G_(t) information in the control trailer 320 or 420 (block 1104).In this regard, the receive processor 242 or 282 may operate togetherwith the controller 234 or 274 to determine the cumulative power levelof the RTS-TRN frame 300 or CTS-TRN 400 frame at the inputs of the oneor more transceivers 226 a through 226 n or 266 a through 266 n.Additionally, the receive processor 242 or 282 may operate together withthe controller 234 or 274 and the receive data processor 244 or 284 toextract the duration information and at least one of the ISF, P_(t), orG_(r)−G_(t) information from the RTS-TRN frame 300 or the CTS-TRN frame400.

The method 1100 further includes storing the power level indication, theduration information, and the at least one of the ISF, P_(t), orG_(r)−G_(t) information for potential subsequent use in estimatingpotential interference at the neighboring device transmitting theRTS-TRN frame 300 or the CTS-TRN frame 400 based on a proposedtransmission scheme (block 1106). In this regard, the controller 234 orthe controller 274 may store the aforementioned information in thememory device(s) 236 or 276, respectively.

The method 1100 further includes determining a proposed transmissionscheme (including a transmit power and reciprocity factor) fortransmitting a signal (e.g., an RTS frame or CTS frame) to a targetdevice (block 1108). This may be for example the third device (630, 730,830) selecting a proposed transmission scheme for sending an RTS frameto the fourth device (640, 740, 840); or the fourth device (640, 740,840) selecting a proposed transmission scheme for sending a CTS frame tothe third device (630, 730, 830), as previously discussed. In thisregard, the controller 234 or 274 may determine the proposedtransmission scheme including a transmit power and the antenna radiationpattern for transmission to the target device. The reciprocity factor isbased on the selected antenna radiation pattern.

The method 1100 further includes determining whether the neighboringdevice, which transmitted the RTS-TRN frame 300 or the CTS-TRN frame400, is communicating based on the duration information in the durationfield 312 or 412, respectively (block 1110). In this regard, thecontroller 234 or 274 may access the duration information from thememory device(s) 236 or 276 to determine whether the neighboring deviceis communicating.

If, in block 1112, it is determined that the neighboring device is notcommunicating, the method 1100 further includes transmitting a signal(e.g., an RTS frame or CTS frame) to the target device in accordancewith the proposed transmission scheme (block 1118). In this regard, thedata source 215 or 255, transmit data processor 220 or 260, framebuilder 222 or 262, transmit processor 224 or 264, transceivers 226 athrough 226 n or 266 a through 266 n, and antennas 230 a through 230 nor 270 a through 270 n operate together to transmit the signal (e.g., anRTS frame or CTS frame) to the target device.

If, on the other hand, in block 1112, it is determined that theneighboring device is communicating, the method 1100 includes estimatingpotential interference at the neighboring device (that transmitted theRTS-TRN frame 300 or CTS-TRN frame 400) based on at least one of theISF, P_(t), or G_(t)−G_(r), and the proposed transmission scheme (block1114). For instance, any suitable one of Equations 1-4 may be used toestimate potential interference at the neighboring device. In thisregard, the controller 234 or 274 may access the received power levelindication of the RTS-TRN frame 300 or CTS-TRN frame 400, at least oneof the ISF, P_(t), or G_(t)−G_(r), and the transmit power andreciprocity factor of the proposed transmission scheme from therespective memory device(s) 236 or 276, and generate the estimatedtransmission scheme based on the aforementioned information.

The method 1100 further includes determining whether the estimatedpotential interference is greater than or equal to a threshold (block1116). As previously discussed, if the estimated potential interferenceis greater than or equal to the threshold, then the proposedtransmission scheme may adversely impact the communications of theneighboring device associated with the received RTS-TRN frame 300 orCTS-TRN frame 400. On the other hand, if the estimated potentialinterference is less than (or equal to) the threshold, then the proposedtransmission scheme may not adversely impact the communications of theneighboring device associated with the received RTS-TRN frame 300 orCTS-TRN frame 400.

If, in block 1116, it is determined that the estimated potentialinterference is less than (or equal to) the threshold, the method 1100further includes transmitting a signal (e.g., an RTS frame or CTS frame)to the target device in accordance with the proposed transmission scheme(block 1118). The operation specified in block 1118 also assumes thatthe estimated potential interference to the device communicating withthe neighboring device is less than (or equal to) the threshold. In thisregard, the data source 215 or 255, transmit data processor 220 or 260,frame builder 222 or 262, transmit processor 224 or 264, transceivers226 a through 226 n or 266 a through 266 n, and antennas 230 a through230 n or 270 a to 270 n operate together to transmit the signal (e.g.,an RTS frame or CTS frame) to the target device.

If, on the other hand, in block 1116, the estimated potentialinterference is greater than or equal to the threshold, the method 1100includes performing an action to eliminate or reduce the potentialinterference at the neighboring device (block 1120). For example, thedevice may decide to withdraw the transmission of the signal (e.g., anRTS frame or CTS frame) to the target device. The device may delay thetransmission of the signal to the target device until after theneighboring device ceases communicating based on the durationinformation in the duration field 312 or 412 of the RTS-TRN frame 300 orCTS-TRN frame 400, respectively.

Alternatively, the device may change the proposed transmission scheme tolower the estimated interference at the neighboring device to less than(or equal to) the threshold. For example, the device may change thetransmit sector for transmitting the signal (e.g., an RTS frame or CTSframe) so as to reduce the estimated interference to less than (or equalto) the threshold. In this regard, the controller 234 or 274 operatestogether with the transmit processor 224 or 264 to change the transmitsector. For instance, the device may generate antenna weights vector(AWV) and corresponding transmit power value for generating the signalto reduce the estimated interference to less than (or equal to) thethreshold.

As another example, the device may change the transmit power of theproposed transmission scheme to lower the transmit power so as to reducethe estimated interference at the neighboring device to less than (orequal to) the threshold. In this regard, the controller 234 or 274operates together with the transmit processor 224 or 264 to change thetransmit power.

FIG. 12 illustrates an example device 1200 according to certain aspectsof the present disclosure. The device 1200 may be configured to operatein an access point (e.g., access point 110) or an access terminal 120(e.g., access terminal 120 a) and to perform one or more of theoperations described herein. The device 1200 includes a processingsystem 1220, and a memory device(s) 1210 coupled to the processingsystem 1220. In the example of the access point 110, the processingsystem 1220 may include one or more of the transmit data processor 220,the frame builder 222, the transmit processor 224, the controller 234,the receive data processor 244, and the receive processor 242. Stillreferring to the example of the access point 110, the memory device(s)1210 may include one or more of the memory device(s) 236 and the datasink 246. Still referring to the example of the access point 110, thetransmit/receive interface may include one or more of the bus interface,the transmit data processor 220, the transmit processor 224, the receivedata processor 244, the receive processor 242, the transceivers 226 athrough 226 n, and the antennas 230 a through 230 n.

In the example of the access terminal 120, the processing system 1220may include one or more of the transmit data processor 260, the framebuilder 262, the transmit processor 264, the controller 274, the receivedata processor 284, and the receive processor 282. Still referring tothe example of the access terminal 120, the memory device(s) 1210 mayinclude one or more of the memory device(s) 276 and the data sink 286.Still referring to the example of the access terminal 120, thetransmit/receive interface 1230 may include one or more of the businterface, the transmit data processor 260, the transmit processor 264,the receive data processor 284, the receive processor 282, thetransceivers 266 a through 266 n, and the antennas 270 a through 270 n.

The memory device(s) 1210 may store instructions that, when executed bythe processing system 1220, cause the processing system 1220 to performone or more of the operations described herein. Exemplaryimplementations of the processing system 1220 are provided below. Thedevice 1200 also comprises transmit/receive circuitry, which may bereferred to herein as a transmit/receive interface 1230, coupled to theprocessing system 1220. The transmit/receive interface 1230 (e.g.,interface bus) may be configured to interface the processing system 1220to a radio frequency (RF) front end, or transmit/receive interface 1230,as discussed further below.

In certain aspects, the processing system 1220 may include one or moreof the following: a transmit data processor (e.g., transmit dataprocessor 220 or 260), a frame builder (e.g., frame builder 222 or 262),a transmit processor (e.g., transmit processor 224 or 264) and/or acontroller (e.g., controller 234 or 274) for performing one or more ofthe operations described herein. In these aspects, the processing system1220 may generate a frame and output the frame to the RF front end forwireless transmission (e.g., to an access point 110 or an accessterminal 120).

In certain aspects, the processing system 1220 may include one or moreof the following: a receive processor (e.g., receive processor 242 or282), a receive data processor (e.g., receive data processor 244 or 284)and/or a controller (e.g., controller 234 and 274) for performing one ormore of the operations described herein. In these aspects, theprocessing system 1220 may receive a frame from the RF front end andprocess the frame according to any one or more of the aspects discussedabove.

In the case of an access terminal 120, the device 1200 may include auser interface 1240 coupled to the processing system 1220. The userinterface 1240 may be configured to receive data from a user (e.g., viakeypad, mouse, joystick, etc.) and provide the data to the processingsystem 1220. The user interface 1240 may also be configured to outputdata from the processing system 1220 to the user (e.g., via a display,speaker, etc.). In this case, the data may undergo additional processingbefore being output to the user. In the case of an access point 110, theuser interface 1240 may be omitted.

FIG. 13 illustrates an exemplary method 1300 for determining potentialinterference in accordance with certain aspects of the disclosure. Themethod 1300 may be implemented by a neighboring device to an originatingdevice or a destination device. For example, method 1300 may beimplemented at the third device (630, 730, 830) to reduce or eliminateinterference at the first device (610, 710, 810) or the second device(620, 720, 820) due to a proposed transmission scheme selected by thethird device (630, 730, 830). Similarly, method 1300 may be implementedat the fourth device (640, 740, 840) to reduce or eliminate interferenceat the first device (610, 710, 810) or the second device (620, 720, 820)due to a proposed transmission scheme selected by the fourth device(640, 740, 840).

The method includes generating at least one frame including informationfrom which at least one first wireless node is able to estimate apotential interference at an apparatus configured to transmit the atleast one frame (block 1302), followed by outputting the at least oneframe for transmission to at least one second wireless node (block1304).

FIG. 14 illustrates an apparatus for wireless communication 1400 thatcorresponds to the exemplary method of FIG. 13. The apparatus forwireless communication 1400 may include a means for generating 1402 atleast one frame including information from which at least one firstwireless node is able to estimate a potential interference at anapparatus configured to transmit the at least one frame. For example,the information may include an additional bit or bits in one or morefields that indicate a potential interference. In another example, thesize and field configuration of the frame may be an indication of thepotential interference.

The apparatus for wireless communication 1400 may include a means foroutputting 1404 that is coupled to the means for generating 1402,configured to output the at least one frame for transmission to at leastone second wireless node. For example, the means for generating 1402,e.g., the processing system 1220, may communicate the at least one framefor transmission to the means for outputting 1404, e.g., thetransmit/receive interface 1230. The means for outputting 1404 maycommunicate the at least one frame to another apparatus for wirelesscommunication.

FIG. 15 illustrates an exemplary method 1500 for performingcommunication operations based on potential interference in accordancewith certain aspects of the disclosure. The method 1500 may beimplemented by a neighboring device to an originating device or adestination device. For example, method 1500 may be implemented at thethird device (630, 730, 830) to reduce or eliminate interference at thefirst device (610, 710, 810) or the second device (620, 720, 820) due toa proposed transmission scheme selected by the third device (630, 730,830). Similarly, method 1500 may be implemented at the fourth device(640, 740, 840) to reduce or eliminate interference at the first device(610, 710, 810) or the second device (620, 720, 820) due to a proposedtransmission scheme selected by the fourth device (640, 740, 840).

The method includes receiving at least one first frame from a firstwireless node (block 1502), estimate a potential interference at thefirst wireless node based on information in the at least one first frameand a proposed transmission scheme for transmitting at least one secondframe to a second wireless node (block 1504), and performing anoperation based on the estimated potential interference (block 1506).

FIG. 16 illustrates an apparatus for wireless communication 1600 thatcorresponds to the exemplary method of FIG. 15. The apparatus forwireless communication 1600 may include a means for receiving 1602 atleast one first frame from a first wireless node. For example, the meansfor receiving the at least one first frame may include thetransmit/receive interface 1230 which may receive the first frame via awireless communication with an access point 110 and/or access terminal120.

The apparatus for wireless communication 1600 may include a means forestimating 1604 a potential interference at the first wireless nodebased on information in the at least one first frame and a proposedtransmission scheme for transmitting at least one second frame to asecond wireless node. For example, the means for estimating 1604 mayinclude the processing system 1220 and the memory device(s) 1210.Estimation of a potential interference may include estimation based onknown values associated with information (e.g., identifier data, or anyother portion of the RTS/CTS portion of the frame) provided in the atleast one first frame.

The apparatus for wireless communication 1600 may include a means forperforming 1606 an operation based on the estimated potentialinterference. For example, the means for performing may include theprocessing system 1220, the memory device(s) 1210, and/or thetransmit/receive interface 1230. The performance of the operation mayinclude transmitting, via the transmit/receive interface 1230, dataassociated with an interference or potential interference at a specificnode.

The apparatus for wireless communication 1600 may include a means forperforming 1606 an operation based on the estimated potentialinterference.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. For example, operations 1300 and 1500 illustrated inFIGS. 13 and 15 correspond to means 1400 and 1600 illustrated in FIGS.14 and 16.

For instance, the controllers (234 and 274) and processing system 1220are each examples of means for configuring a subset of a plurality of RFreceiver chains coupled to respective antennas to receive in anomnidirectional manner. The controllers (234 and 274), receiveprocessors (242 and 282), receive data processors (244 and 284), andprocessing system 1220 are each examples of means for determining afirst energy level of at least one signal received via the subset whilethe subset of RF receiver chains is configured to receive in theomnidirectional manner. The controllers (234 and 274), receiveprocessors (242 and 282), receive data processors (244 and 284), andprocessing system 1220 are each examples of means for configuring theplurality of RF receiver chains to directionally receive from a targetdevice based on the first energy level. The controllers (234 and 274),receive processors (242 and 282), receive data processors (244 and 284),and processing system 1220 are each examples of means for determining asecond energy level of the at least one signal received via the RFreceiver chains while the RF receiver chains are configured todirectionally receive from the target device. The controllers (234 and274) and processing system 1220 are each examples of means forgenerating data from the at least one signal based on the second energylevel.

The processing system 1220 and frame builders (222 and 262) are eachexamples of means for generating a first frame including a Request toSend (RTS) portion and a first beam training sequence. Thetransmit/receive interface 1230 and transmit processors (224 and 264)are each examples of means for outputting the first frame fortransmission to a device. The transmit/receive interface 1230 andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for configuring an antenna to transmit the first framein a directional manner. The transmit/receive interface 1230 andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for configuring an antenna to transmit the first framewith an antenna radiation pattern having a primary lobe aimedsubstantially at the device.

The processing system 1220, transceivers 226 a through 226 n and 266 athrough 266 n, and receive processors 242 and 282 are each examples ofmeans for receiving a second frame from the device in response totransmitting the first frame, wherein the second frame comprises a Clearto Send (CTS) portion and a second beam training sequence. Theprocessing system 1220 and frame builders (222 and 262) are eachexamples of means for generating one or more data frames in response toreceiving the second frame. The transmit/receive interface 1230 andtransmit processors (224 and 264) are each examples of means foroutputting the one or more data frames for transmission to the device.

The transmit/receive interface 1230 and transceivers 226 a through 226n, 266 a through 266 n are each examples of means for configuring anantenna to transmit the one or more data frames with an antennatransmission radiation pattern having a primary lobe aimed substantiallyat the device based on the second beam training sequence. The processingsystem 1220, transceivers 226 a through 226 n and 266 a through 266 n,and receive processors (242 and 282) are each examples of means forreceiving one or more acknowledgement (ACK) frames from the device inresponse to transmitting the one or more data frames. Thetransmit/receive interface 1230 and transceivers 226 a through 226 n and266 a through 266 n are each examples of means for configuring anantenna to receive the one or more ACK frames 500 with an antennaradiation pattern having a primary lobe aimed substantially at thedevice based on the second beam training sequence.

The processing system 1220 and frame builders (222 and 262) are eachexamples of means for generating a first frame including a Clear to Send(CTS) portion and a first beam training sequence. The transmit/receiveinterface 1230 and transmit processors (224 and 264) are each examplesof means for outputting the first frame for transmission to a device.The processing system 1220, controllers (234 and 274), and framebuilders (222 and 262) are each examples of means for generating thefirst frame in response to receiving a Request to Send (RTS) frame fromthe device.

The transmit/receive interface 1230 and transceivers 226 a through 226 nand 266 a through 266 n are each examples of means for configuring anantenna to receive the RTS frame in an omnidirectional manner. Theprocessing system 1220, controllers (234 and 274), and frame builders(222 and 262) are each examples of means for generating the first framein response to receiving a second frame comprising a Request to Send(RTS) portion and a second beam training sequence. The transmit/receiveinterface 1230, controllers (234 and 274), and transceivers 226 athrough 226 n and 266 a through 266 n are each examples of means forreceiving one or more data frames from the device in response totransmitting the first frame.

The transmit/receive interface 1230, controllers (234 and 274), andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for configuring an antenna to receive the one or moredata frames with an antenna radiation pattern having a primary lobeaimed substantially at the device based on a second frame comprising anRTS portion and a second beam training sequence. The processing system1220 and frame builders (222 and 262) are each examples of means forgenerating one or more acknowledgement (ACK) frames 500 in response toreceiving the one or more data frames. The transmit/receive interface1230 and transmit processors (224 and 264) are each examples of meansfor outputting the one or more ACK frames 500 for transmission to thedevice. The transmit/receive interface 1230, controllers (234 and 274),and transceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for configuring an antenna to transmit the one or moreACK frames 500 with an antenna radiation pattern having a primary lobeaimed substantially at the device based on a second frame comprising anRTS portion and a second beam training sequence.

The processing system 1220 and receive processors (242 and 282) are eachexamples of means for receiving a first frame comprising a first Requestto Send (RTS) portion and a first beam training sequence from a firstdevice (610, 710, 810). The transmit/receive interface 1230, controllers(234 and 274), and transceivers 226 a through 226 n and 266 a through266 n are each examples of means for configuring an antenna in a firstconfiguration based on the first beam training sequence. The processingsystem 1220 and frame builders (222 and 262) are each examples of meansfor generating a second frame. The transmit/receive interface 1230 andtransmit processors (224 and 264) are each examples of means foroutputting the second frame for transmission to a second device (620,720, 820) via the antenna while the antenna is configured in the firstconfiguration.

The processing system 1220 and controllers (234 and 274) are eachexamples of means for determining a duration in which the first device(610, 710, 810) will be communicating with a third device (630, 730,830) based on the first RTS portion of the first frame. Thetransmit/receive interface 1230, controllers (234 and 274), andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for reconfiguring the antenna in a secondconfiguration in response to determining the first device (610, 710,810) is no longer communicating with the third device (630, 730, 830)based on the duration. The processing system 1220 and frame builders(222 and 262) are each examples of means for generating a third frame.The transmit/receive interface 1230 and transmit processors (224 and264) are each examples of means for outputting the third frame fortransmission to the second device (620, 720, 820) via the antenna whilethe antenna is configured in the second configuration.

The processing system 1220 and the receive processors (242 and 282) areeach examples of means for receiving a third frame including a Clear toSend (CTS) portion and a second beam training sequence from a thirddevice (630, 730, 830). The processing system 1220 and controllers (234and 274) are each examples of means for determining a duration in whichthe first device (610, 710, 810) will be communicating with the thirddevice (630, 730, 830) based on at least one of the first RTS portion ofthe first frame or the CTS portion of the third frame. Thetransmit/receive interface 1230, controllers (234 and 274), andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for reconfiguring the antenna in a secondconfiguration in response to determining that the first device (610,710, 810) is no longer communicating with the third device (630, 730,830) based on the duration. The processing system 1220 and framebuilders (222 and 262) are each examples of means for generating a thirdframe. The transmit/receive interface 1230 and transmit processors (224and 264) are each examples of means for outputting the third frame fortransmission to the second device (620, 720, 820) via the antenna whilethe antenna is configured in the second configuration.

The processing system 1220 and receive processors (242 and 282) are eachexamples of means for receiving a first frame comprising a first Clearto Send (CTS) portion and a first beam training sequence from a firstdevice (610, 710, 810). The transmit/receive interface 1230, controllers(234 and 274), and transceivers 226 a through 226 n and 266 a through266 n are each examples of means for configuring an antenna in a firstconfiguration based on the first beam training sequence. The processingsystem 1220 and frame builders (222 and 262) are each examples of meansfor generating a second frame. The transmit/receive interface 1230 andtransmit processors (224 and 264) are each examples of means foroutputting the second frame for transmission to a second device (620,720, 820) via the antenna while the antenna is configured in the firstconfiguration.

The processing system 1220 and controllers (234 and 274) are eachexamples of means for determining a duration in which the first device(610, 710, 810) will be communicating with a third device (630, 730,830) based on the first CTS portion of the first frame. Thetransmit/receive interface 1230, controllers (234 and 274), andtransceivers 226 a through 226 n and 266 a through 266 n are eachexamples of means for reconfiguring the antenna in a secondconfiguration in response to determining the first device (610, 710,810) is no longer communicating with the third device (630, 730, 830)based on the duration. The processing system 1220 and frame builders(222 and 262) are each examples of means for generating a third frame.The transmit/receive interface 1230 and transmit processors (224 and264) are each examples of means for outputting the third frame fortransmission to the second device (620, 720, 820) via the antenna whilethe antenna is configured in the second configuration.

In some cases, rather than actually transmitting a frame a device mayhave an interface to output a frame for transmission (a means foroutputting). For example, the processing system 1220 may output a frame,via a bus interface, to the RF front end, otherwise referred to hereinas the transmit/receive interface 1230, for transmission. Similarly,rather than actually receiving a frame, a device may have an interfaceto obtain a frame received from another device (a means for obtaining).For example, a processor may obtain (or receive) a frame, via a businterface, from an RF front end for reception.

The processing system 1220 and one or more of the transmit processors(224 and 264) and the controllers (234 and 274) are each examples ofmeans for modifying the proposed transmission scheme by changing thetransmit power. In certain aspects, the processing system 1220, thetransmit data processors (220 and 260), the frame builders (222 and262), the transmit processors (224 or 264), and/or the controllers (234and 274) are each examples of a means for performing an operation basedon the estimated potential interference. In other aspects, theprocessing system 1220, the receive processors (242 and 282), thereceive data processors (244 or 284), and/or the controllers (234 and274) are examples of means for performing an operation based on theestimated potential interference. The processing system 1220 and one ormore of the transmit processors (224 and 264) and the controllers (234and 274) are each examples of means for estimating a potentialinterference at the first wireless node.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thepresent disclosure may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in any form of storage medium that is knownin the art. Some examples of storage media that may be used includerandom access memory (RAM), read only memory (ROM), flash memory,erasable programmable read-only memory (EPROM), electrically erasableprogrammable read-only memory (EEPROM), registers, a hard disk, aremovable disk, a CD-ROM and so forth. A software module may comprise asingle instruction, or many instructions, and may be distributed overseveral different code segments, among different programs, and acrossmultiple storage media. A storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware, or any combination thereof. If implemented in hardware, anexample hardware configuration may comprise a processing system in awireless node. The processing system may be implemented with a busarchitecture. The bus may include any number of interconnecting busesand bridges depending on the specific application of the processingsystem and the overall design constraints. The bus may link togethervarious circuits including a processor, machine-readable media, and thebus interface. The bus interface may be used to connect a networkadapter, among other things, to the processing system via the bus. Thenetwork adapter may be used to implement the signal processing functionsof the physical (PHY) layer. In the case of an access terminal 120 (forexample, see FIGS. 1, 2, and 12), a user interface (e.g., keypad,display, mouse, joystick, etc.) may also be connected to the businterface. The bus may also link various other circuits such as timingsources, peripherals, voltage regulators, power management circuits, andthe like, which are well known in the art, and therefore, will not bedescribed any further.

The processor may be responsible for managing the bus and generalprocessing, including the execution of software stored on themachine-readable media. The processor may be implemented with one ormore general-purpose and/or special-purpose processors. Examples includemicroprocessors, microcontrollers, DSP processors, and other circuitrythat can execute software. Software shall be construed broadly to meaninstructions, data, or any combination thereof, whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. Machine-readable media may include, by way ofexample, RAM (Random Access Memory), flash memory, ROM (Read OnlyMemory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product. The computer-program product may comprisepackaging materials.

In a hardware implementation, the machine-readable media may be part ofthe processing system separate from the processor. However, as thoseskilled in the art will readily appreciate, the machine-readable media,or any portion thereof, may be external to the processing system. By wayof example, the machine-readable media may include a transmission line,a carrier wave modulated by data, and/or a computer product separatefrom the wireless node, all which may be accessed by the processorthrough the bus interface. Alternatively, or in addition, themachine-readable media, or any portion thereof, may be integrated intothe processor, such as the case may be with cache and/or generalregister files.

The processing system may be configured as a general-purpose processingsystem with one or more microprocessors providing the processorfunctionality and external memory providing at least a portion of themachine-readable media, all linked together with other supportingcircuitry through an external bus architecture. Alternatively, theprocessing system may be implemented with an ASIC (Application SpecificIntegrated Circuit) with the processor, the bus interface, the userinterface in the case of an access terminal), supporting circuitry, andat least a portion of the machine-readable media integrated into asingle chip, or with one or more FPGAs (Field Programmable Gate Arrays),PLDs (Programmable Logic Devices), controllers, state machines, gatedlogic, discrete hardware components, or any other suitable circuitry, orany combination of circuits that can perform the various functionalitydescribed throughout this disclosure. Those skilled in the art willrecognize how best to implement the described functionality for theprocessing system depending on the particular application and theoverall design constraints imposed on the overall system.

The machine-readable media may comprise a number of software modules.The software modules include instructions that, when executed by theprocessor, cause the processing system to perform various functions. Thesoftware modules may include a transmission module and a receivingmodule. Each software module may reside in a single storage device or bedistributed across multiple storage devices. By way of example, asoftware module may be loaded into RAM from a hard drive when atriggering event occurs. During execution of the software module, theprocessor may load some of the instructions into cache to increaseaccess speed. One or more cache lines may then be loaded into a generalregister file for execution by the processor. When referring to thefunctionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a computer. By way of example,and not limitation, such computer-readable media can comprise RAM, ROM,EEPROM, CD-ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other medium that can be used tocarry or store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared (IR),radio, and microwave, then the coaxial cable, fiber optic cable, twistedpair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For certain aspects, the computer program product may includepackaging material.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by an access terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that an accessterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communications, comprising:generating at least one frame including information from which at leastone first wireless node is able to estimate a potential interference atan apparatus configured to transmit the at least one frame, wherein theinformation includes an interference sensitivity factor (ISF) related toa transmit power and a reciprocity factor of the apparatus; andoutputting the at least one frame for transmission to at least onesecond wireless node.
 2. The method of claim 1, wherein the transmitpower is associated with transmitting the at least one frame to the atleast one second wireless node.
 3. The method of claim 1, wherein the atleast one frame comprises a plurality of frames, and wherein the ISF isrelated to a plurality of transmit powers for transmitting the pluralityof frames, respectively.
 4. The method of claim 3, wherein the ISF isrelated to an average or maximum of the plurality of transmit powers fortransmitting the plurality of frames.
 5. The method of claim 1, whereinthe reciprocity factor is related to an antenna transmit gain and anantenna receive gain associated with an antenna used for transmittingthe at least one frame to and receiving at least one other frame fromthe at least one second wireless node, respectively.
 6. The method ofclaim 1, wherein the transmit power is associated with transmitting theat least one frame to the at least one second wireless node and thereciprocity factor is associated with an antenna used for transmittingthe at least one frame to and receiving at least one other frame fromthe at least one second wireless node, respectively.
 7. The method ofclaim 1, wherein the ISF is related to a receive sensitivity forreceiving at least one other frame from the at least one second wirelessnode.
 8. The method of claim 1, wherein the information comprises areceive sensitivity for receiving at least one other frame from the atleast one second wireless node.
 9. The method of claim 1, wherein theinformation comprises an antenna receive gain and an antenna transmitgain associated with an antenna used for transmitting the at least oneframe to and receiving at least one other frame from the at least onesecond wireless node, respectively.
 10. The method of claim 1, whereinthe at least one frame comprises a Request to Send (RTS) frame.
 11. Themethod of claim 10, wherein the RTS frame comprises a control trailerhaving the information.
 12. The method of claim 1, wherein the at leastone frame comprises a Clear to Send (CTS) frame.
 13. The method of claim12, wherein the CTS frame comprises a control trailer having theinformation.
 14. An apparatus for wireless communications, comprising:means for generating at least one frame including information from whichat least one first wireless node is able to estimate a potentialinterference at the apparatus, wherein the information includes aninterference sensitivity factor (ISF) related to a transmit power and areciprocity factor of the apparatus; and means for outputting the atleast one frame for transmission to at least one second wireless node.15. The apparatus of claim 14, wherein the transmit power is associatedwith transmitting the at least one frame to the at least one secondwireless node.
 16. The apparatus of claim 14, wherein the at least oneframe comprises a plurality of frames, and wherein the ISF is related toa plurality of transmit powers for transmitting the plurality of frames,respectively.
 17. The apparatus of claim 16, wherein the ISF is relatedto an average or maximum of the plurality of transmit powers fortransmitting the plurality of frames.
 18. The apparatus of claim 14,wherein the reciprocity factor is related to an antenna transmit gainand an antenna receive gain associated with an antenna used fortransmitting the at least one frame to and receiving at least one otherframe from the at least one second wireless node, respectively.
 19. Theapparatus of claim 14, wherein the transmit power is associated withtransmitting the at least one frame to the at least one second wirelessnode and an antenna transmit gain and an antenna receive gain associatedwith an antenna used for transmitting the at least one frame to andreceiving the at least one frame from the at least one second wirelessnode, respectively.
 20. The apparatus of claim 14, wherein the ISF isrelated to a receive sensitivity for receiving at least one other framefrom the at least one second wireless node.
 21. The apparatus of claim14, wherein the information comprises a receive sensitivity forreceiving at least one other frame from the at least one second wirelessnode.
 22. The apparatus of claim 14, wherein the information comprisesan antenna receive gain and an antenna transmit gain associated with anantenna used for transmitting the at least one frame to the at least onesecond wireless node.
 23. The apparatus of claim 14, wherein the atleast one frame comprises a Request to Send (RTS) frame.
 24. Theapparatus of claim 23, wherein the RTS frame comprises a control trailerhaving the information.
 25. The apparatus of claim 14, wherein the atleast one frame comprises a Clear to Send (CTS) frame.
 26. The apparatusof claim 25, wherein the CTS frame comprises a control trailer havingthe information.
 27. A method for wireless communications, comprising:receiving at least one first frame from a first wireless node;estimating a potential interference at the first wireless node based oninformation in the at least one first frame and a proposed transmissionscheme for transmitting at least one second frame to a second wirelessnode, wherein the information includes an interference sensitivityfactor (ISF) related to a transmit power and a reciprocity factor of thefirst wireless node; and performing an operation based on the estimatedpotential interference.
 28. The method of claim 27, wherein the transmitpower is associated with transmission of the at least one first frame bythe first wireless node.
 29. The method of claim 27, wherein the atleast one first frame comprises a plurality of first frames, and whereinthe ISF is related to a plurality of transmit powers for transmittingthe plurality of first frames, respectively.
 30. The method of claim 29,wherein the ISF is related to an average or maximum of the transmitpowers for transmitting the plurality of first frames.
 31. The method ofclaim 27, wherein the reciprocity factor is related to an antennatransmit gain and an antenna receive gain associated with an antennaused for transmitting the at least one first frame and receiving atleast one third frame by the first wireless node, respectively.
 32. Themethod of claim 27, wherein the transmit power is associated withtransmitting the at least one first frame by the first wireless node andan antenna transmit gain and an antenna receive gain associated with anantenna used for transmitting the at least one first frame and receivingat least one third frame by the first wireless node, respectively. 33.The method of claim 27, wherein the ISF is related to a receivesensitivity for receiving at least one third frame by the first wirelessnode.
 34. The method of claim 27, wherein the information comprises areceive sensitivity for receiving at least one third frame by the firstwireless node.
 35. The method of claim 27, wherein the informationcomprises an antenna receive gain and an antenna transmit gainassociated with an antenna used for transmitting the at least one firstframe and receiving at least one third frame by the first wireless node,and wherein estimating the potential interference at the first wirelessnode is based on the information.
 36. The method of claim 27, whereinestimating the potential interference at the first wireless node isbased on a power level of the received at least one first frame.
 37. Themethod of claim 27, wherein the proposed transmission scheme includesthe transmit power for transmitting the at least one second frame to thesecond wireless node, and wherein estimating the potential interferenceat the first wireless node is based on the transmit power.
 38. Themethod of claim 27, wherein the proposed transmission scheme includes anantenna transmit gain and an antenna receive gain associated with anantenna for transmitting the at least one second frame to and receivingat least one third frame from the second wireless node, whereinestimating the potential interference at the first wireless node isbased on the reciprocity factor.
 39. The method of claim 27, wherein theat least one first frame comprises a Request to Send (RTS) frame or aClear to Send (CTS) frame, wherein the RTS frame or the CTS framecomprises a control trailer having the information.
 40. The method ofclaim 27, wherein the at least one first frame includes a Request toSend (RTS) frame or a Clear to Send (CTS) frame, wherein estimating thepotential interference at the first wireless node is based oninformation in a duration field of the RTS frame or CTS frame.
 41. Themethod of claim 27, wherein performing the operation comprisesoutputting the at least one second frame for transmission to the secondwireless node in accordance with the proposed transmission scheme if theestimated potential interference is less than or equal to a threshold.42. The method of claim 27, wherein the operation comprises at least oneof generating antenna weights vector (AWV) or transmit power value fortransmitting the at least one second frame via a set of antennas inaccordance with the proposed transmission scheme, and wherein aninterface is configured to output the at least one second frame fortransmission to the second wireless node in accordance with the proposedtransmission scheme if the estimated potential interference is less thanor equal to a threshold.
 43. The method of claim 27, wherein the atleast one first frame further comprises duration information, andfurther wherein performing the operation comprises generating the atleast one second frame if the estimated potential interference isgreater than or equal to a threshold and outputting the at least onesecond frame for transmission to the second wireless node based on theduration information.
 44. The method of claim 27, wherein performing theoperation comprises: generating the at least one second frame; modifyingthe proposed transmission scheme for transmitting the at least onesecond frame to the second wireless node if the estimated potentialinterference is greater than or equal to a threshold; and outputting theat least one second frame for transmission to the second wireless nodein accordance with the modified transmission scheme.
 45. The method ofclaim 44, wherein the proposed transmission scheme includes a transmitpower for transmitting the at least one second frame to the secondwireless node, and wherein performing the operation comprises:generating the at least one second frame; modifying the proposedtransmission scheme by changing the transmit power; and outputting theat least one second frame for transmission to the second wireless nodein accordance with the modified transmission scheme.
 46. The method ofclaim 44, wherein the proposed transmission scheme includes atransmission sector for transmitting the at least one second frame tothe second wireless node, and wherein performing the operationcomprises: generating the at least one second frame; modifying theproposed transmission scheme by changing the transmission sector; andoutputting the at least one second frame for transmission to the secondwireless node in accordance with the modified transmission scheme. 47.The method of claim 44, wherein the proposed transmission schemeincludes an antenna weights vector (AWV) for transmitting the at leastone second frame to the second wireless node via a set of antennas,wherein performing the operation comprises: generating the at least onesecond frame; modifying the proposed transmission scheme by changing theAWV; and outputting the at least one second frame for transmission tothe second wireless node in accordance with the modified transmissionscheme.